mirror of
https://github.com/torvalds/linux.git
synced 2026-06-01 02:53:36 +02:00
v7.0
61 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Lorenzo Stoakes
|
53f1d93644 |
mm: make vm_area_desc utilise vma_flags_t only
Now we have eliminated all uses of vm_area_desc->vm_flags, eliminate this field, and have mmap_prepare users utilise the vma_flags_t vm_area_desc->vma_flags field only. As part of this change we alter is_shared_maywrite() to accept a vma_flags_t parameter, and introduce is_shared_maywrite_vm_flags() for use with legacy vm_flags_t flags. We also update struct mmap_state to add a union between vma_flags and vm_flags temporarily until the mmap logic is also converted to using vma_flags_t. Also update the VMA userland tests to reflect this change. Link: https://lkml.kernel.org/r/fd2a2938b246b4505321954062b1caba7acfc77a.1769097829.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Cc: Damien Le Moal <dlemoal@kernel.org> Cc: "Darrick J. Wong" <djwong@kernel.org> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Yury Norov <ynorov@nvidia.com> Cc: Chris Mason <clm@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Liam R. Howlett
|
a8700d42b0 |
mm: use unmap_desc struct for freeing page tables
Pass through the unmap_desc to free_pgtables() because it almost has everything necessary and is already on the stack. Updates testing code as necessary. No functional changes intended. [Liam.Howlett@oracle.com: fix up unmap desc use on exit_mmap()] Link: https://lkml.kernel.org/r/20260210214214.364856-1-Liam.Howlett@oracle.com Link: https://lkml.kernel.org/r/20260121164946.2093480-12-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Kairui Song <kasong@tencent.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: SeongJae Park <sj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Liam R. Howlett
|
0df5a8d394 |
mm/vma: use unmap_desc in exit_mmap() and vms_clear_ptes()
Convert vms_clear_ptes() to use unmap_desc to call unmap_vmas() instead of the large argument list. The UNMAP_STATE() cannot be used because the vma iterator in the vms does not point to the correct maple state (mas_detach), and the tree_end will be set incorrectly. Setting up the arguments manually avoids setting the struct up incorrectly and doing extra work to get the correct pagetable range. exit_mmap() also calls unmap_vmas() with many arguments. Using the unmap_all_init() function to set the unmap descriptor for all vmas makes this a bit easier to read. Update to the vma test code is necessary to ensure testing continues to function. No functional changes intended. Link: https://lkml.kernel.org/r/20260121164946.2093480-10-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Kairui Song <kasong@tencent.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: SeongJae Park <sj@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Liam R. Howlett
|
5b6626a76a |
mm: introduce unmap_desc struct to reduce function arguments
The unmap_region code uses a number of arguments that could use better documentation. With the addition of a descriptor for unmap (called unmap_desc), the arguments can be more self-documenting and increase the descriptions within the declaration. No functional change intended Link: https://lkml.kernel.org/r/20260121164946.2093480-9-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Kairui Song <kasong@tencent.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: SeongJae Park <sj@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Liam R. Howlett
|
243de0c0dc |
mm/vma: add page table limit to unmap_region()
The unmap_region() calls need to pass through the page table limit for a future patch. No functional changes intended. Link: https://lkml.kernel.org/r/20260121164946.2093480-7-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Kairui Song <kasong@tencent.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: SeongJae Park <sj@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Liam R. Howlett
|
23bd03a9a2 |
mm/vma: add limits to unmap_region() for vmas
Add a limit to the vma search instead of using the start and end of the one passed in. No functional changes intended. Link: https://lkml.kernel.org/r/20260121164946.2093480-5-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Kairui Song <kasong@tencent.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: SeongJae Park <sj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Wentao Guan
|
7db0787000 |
mm: cleanup vma_iter_bulk_alloc
commit |
||
|
Kevin Lourenco
|
62451ae347 |
mm: fix minor spelling mistakes in comments
Correct several typos in comments across files in mm/ [akpm@linux-foundation.org: also fix comment grammar, per SeongJae] Link: https://lkml.kernel.org/r/20251218150906.25042-1-klourencodev@gmail.com Signed-off-by: Kevin Lourenco <klourencodev@gmail.com> Reviewed-by: SeongJae Park <sj@kernel.org> Acked-by: David Hildenbrand (Red Hat) <david@kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
61f67c230a |
mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge
Patch series "mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge", v2. Commit |
||
|
Lorenzo Stoakes
|
64212ba02e |
mm: implement sticky VMA flags
It is useful to be able to designate that certain flags are 'sticky', that is, if two VMAs are merged one with a flag of this nature and one without, the merged VMA sets this flag. As a result we ignore these flags for the purposes of determining VMA flag differences between VMAs being considered for merge. This patch therefore updates the VMA merge logic to perform this action, with flags possessing this property being described in the VM_STICKY bitmap. Those flags which ought to be ignored for the purposes of VMA merge are described in the VM_IGNORE_MERGE bitmap, which the VMA merge logic is also updated to use. As part of this change we place VM_SOFTDIRTY in VM_IGNORE_MERGE as it already had this behaviour, alongside VM_STICKY as sticky flags by implication must not disallow merge. Ultimately it seems that we should make VM_SOFTDIRTY a sticky flag in its own right, but this change is out of scope for this series. The only sticky flag designated as such is VM_MAYBE_GUARD, so as a result of this change, once the VMA flag is set upon guard region installation, VMAs with guard ranges will now not have their merge behaviour impacted as a result and can be freely merged with other VMAs without VM_MAYBE_GUARD set. Also update the comments for vma_modify_flags() to directly reference sticky flags now we have established the concept. We also update the VMA userland tests to account for the changes. Link: https://lkml.kernel.org/r/22ad5269f7669d62afb42ce0c79bad70b994c58d.1763460113.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrei Vagin <avagin@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand (Red Hat) <david@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Jann Horn <jannh@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
9119d6c209 |
mm: update vma_modify_flags() to handle residual flags, document
The vma_modify_*() family of functions each either perform splits, a merge or no changes at all in preparation for the requested modification to occur. When doing so for a VMA flags change, we currently don't account for any flags which may remain (for instance, VM_SOFTDIRTY) despite the requested change in the case that a merge succeeded. This is made more important by subsequent patches which will introduce the concept of sticky VMA flags which rely on this behaviour. This patch fixes this by passing the VMA flags parameter as a pointer and updating it accordingly on merge and updating callers to accommodate for this. Additionally, while we are here, we add kdocs for each of the vma_modify_*() functions, as the fact that the requested modification is not performed is confusing so it is useful to make this abundantly clear. We also update the VMA userland tests to account for this change. Link: https://lkml.kernel.org/r/23b5b549b0eaefb2922625626e58c2a352f3e93c.1763460113.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrei Vagin <avagin@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand (Red Hat) <david@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Jann Horn <jannh@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
cf1d98f44d |
mm/vma: remove unused function, make internal functions static
unlink_file_vma() is not used by anything, so remove it. vma_link() and vma_link_file() are only used within mm/vma.c, so make them static. Link: https://lkml.kernel.org/r/f2ab9ea051225a02e6d1d45a7608f4e149220117.1760959442.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Baoquan He <bhe@redhat.com> Cc: Chatre, Reinette <reinette.chatre@intel.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Dave Martin <dave.martin@arm.com> Cc: Dave Young <dyoung@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Hugh Dickins <hughd@google.com> Cc: James Morse <james.morse@arm.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kevin Tian <kevin.tian@intel.com> Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nicolas Pitre <nico@fluxnic.net> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Robin Murohy <robin.murphy@arm.com> Cc: Sumanth Korikkar <sumanthk@linux.ibm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
af6703838e |
mm: specify separate file and vm_file params in vm_area_desc
Patch series "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()", v2. As part of the efforts to eliminate the problematic f_op->mmap callback, a new callback - f_op->mmap_prepare was provided. While we are converting these callbacks, we must deal with 'stacked' filesystems and drivers - those which in their own f_op->mmap callback invoke an inner f_op->mmap callback. To accomodate for this, a compatibility layer is provided that, via vfs_mmap(), detects if f_op->mmap_prepare is provided and if so, generates a vm_area_desc containing the VMA's metadata and invokes the call. So far, we have provided desc->file equal to vma->vm_file. However this is not necessarily valid, especially in the case of stacked drivers which wish to assign a new file after the inner hook is invoked. To account for this, we adjust vm_area_desc to have both file and vm_file fields. The .vm_file field is strictly set to vma->vm_file (or in the case of a new mapping, what will become vma->vm_file). However, .file is set to whichever file vfs_mmap() is invoked with when using the compatibilty layer. Therefore, if the VMA's file needs to be updated in .mmap_prepare, desc->vm_file should be assigned, whilst desc->file should be read. No current f_op->mmap_prepare users assign desc->file so this is safe to do. This makes the .mmap_prepare callback in the context of a stacked filesystem or driver completely consistent with the existing .mmap implementations. While we're here, we do a few small cleanups, and ensure that we const-ify things correctly in the vm_area_desc struct to avoid hooks accidentally trying to assign fields they should not. This patch (of 2): Stacked filesystems and drivers may invoke mmap hooks with a struct file pointer that differs from the overlying file. We will make this functionality possible in a subsequent patch. In order to prepare for this, let's update vm_area_struct to separately provide desc->file and desc->vm_file parameters. The desc->file parameter is the file that the hook is expected to operate upon, and is not assignable (though the hok may wish to e.g. update the file's accessed time for instance). The desc->vm_file defaults to what will become vma->vm_file and is what the hook must reassign should it wish to change the VMA"s vma->vm_file. For now we keep desc->file, vm_file the same to remain consistent. No f_op->mmap_prepare() callback sets a new vma->vm_file currently, so this is safe to change. While we're here, make the mm_struct desc->mm pointers at immutable as well as the desc->mm field itself. As part of this change, also update the single hook which this would otherwise break - mlock_future_ok(), invoked by secretmem_mmap_prepare()). We additionally update set_vma_from_desc() to compare fields in a more logical fashion, checking the (possibly) user-modified fields as the first operand against the existing value as the second one. Additionally, update VMA tests to accommodate changes. Link: https://lkml.kernel.org/r/cover.1756920635.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/3fa15a861bb7419f033d22970598aa61850ea267.1756920635.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Pedro Falcato <pfalcato@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Ye Liu
|
e4fe1388df |
mm: fix typos in VMA comments
Fix the following typos in VMA-related files: 1. "operationr" -> "operation" in mm/vma.h 2. "initialisaing" -> "initializing" in mm/vma_init.c Link: https://lkml.kernel.org/r/20250814073800.13617-1-ye.liu@linux.dev Signed-off-by: Ye Liu <liuye@kylinos.cn> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
8b2914162a |
mm/mseal: small cleanups
Drop the wholly unnecessary set_vma_sealed() helper(), which is used only once, and place VMA_ITERATOR() declarations in the correct place. Retain vma_is_sealed(), and use it instead of the confusingly named can_modify_vma(), so it's abundantly clear what's being tested, rather then a nebulous sense of 'can the VMA be modified'. No functional change intended. Link: https://lkml.kernel.org/r/98cf28d04583d632a6eb698e9ad23733bb6af26b.1753431105.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Jeff Xu <jeffxu@chromium.org> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
d0b47a6866 |
mm/mseal: update madvise() logic
The madvise() logic is inexplicably performed in mm/mseal.c - this ought to be located in mm/madvise.c. Additionally can_modify_vma_madv() is inconsistently named and, in combination with is_ro_anon(), is very confusing logic. Put a static function in mm/madvise.c instead - can_madvise_modify() - that spells out exactly what's happening. Also explicitly check for an anon VMA. Also add commentary to explain what's going on. Essentially - we disallow discarding of data in mseal()'d mappings in instances where the user couldn't otherwise write to that data. We retain the existing behaviour here regarding MAP_PRIVATE mappings of file-backed mappings, which entails some complexity - while this, strictly speaking - appears to violate mseal() semantics, it may interact badly with users which expect to be able to madvise(MADV_DONTNEED) .text mappings for instance. We may revisit this at a later date. No functional change intended. Link: https://lkml.kernel.org/r/492a98d9189646e92c8f23f4cce41ed323fe01df.1753431105.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Acked-by: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Kees Cook <kees@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
cfea89210a |
mm/vma: refactor vma_modify_flags_name() to vma_modify_name()
The single instance in which we use this function doesn't actually need to change VMA flags, so remove this parameter and update the caller accordingly. [lorenzo.stoakes@oracle.com: correct comment] Link: https://lkml.kernel.org/r/77f45b2e-a748-4635-9381-a5051091087f@lucifer.local Link: https://lkml.kernel.org/r/20250714135839.178032-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
bfbe71109f |
mm: update core kernel code to use vm_flags_t consistently
The core kernel code is currently very inconsistent in its use of vm_flags_t vs. unsigned long. This prevents us from changing the type of vm_flags_t in the future and is simply not correct, so correct this. While this results in rather a lot of churn, it is a critical pre-requisite for a future planned change to VMA flag type. Additionally, update VMA userland tests to account for the changes. To make review easier and to break things into smaller parts, driver and architecture-specific changes is left for a subsequent commit. The code has been adjusted to cascade the changes across all calling code as far as is needed. We will adjust architecture-specific and driver code in a subsequent patch. Overall, this patch does not introduce any functional change. Link: https://lkml.kernel.org/r/d1588e7bb96d1ea3fe7b9df2c699d5b4592d901d.1750274467.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by: Kees Cook <kees@kernel.org> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Jan Kara <jack@suse.cz> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Acked-by: Zi Yan <ziy@nvidia.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Jann Horn <jannh@google.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
bb666b7c27 |
mm: add mmap_prepare() compatibility layer for nested file systems
Nested file systems, that is those which invoke call_mmap() within their own f_op->mmap() handlers, may encounter underlying file systems which provide the f_op->mmap_prepare() hook introduced by commit |
||
|
Pu Lehui
|
2b12d06c37 |
mm: fix uprobe pte be overwritten when expanding vma
Patch series "Fix uprobe pte be overwritten when expanding vma".
This patch (of 4):
We encountered a BUG alert triggered by Syzkaller as follows:
BUG: Bad rss-counter state mm:00000000b4a60fca type:MM_ANONPAGES val:1
And we can reproduce it with the following steps:
1. register uprobe on file at zero offset
2. mmap the file at zero offset:
addr1 = mmap(NULL, 2 * 4096, PROT_NONE, MAP_PRIVATE, fd, 0);
3. mremap part of vma1 to new vma2:
addr2 = mremap(addr1, 4096, 2 * 4096, MREMAP_MAYMOVE);
4. mremap back to orig addr1:
mremap(addr2, 4096, 4096, MREMAP_MAYMOVE | MREMAP_FIXED, addr1);
In step 3, the vma1 range [addr1, addr1 + 4096] will be remap to new vma2
with range [addr2, addr2 + 8192], and remap uprobe anon page from the vma1
to vma2, then unmap the vma1 range [addr1, addr1 + 4096].
In step 4, the vma2 range [addr2, addr2 + 4096] will be remap back to the
addr range [addr1, addr1 + 4096]. Since the addr range [addr1 + 4096,
addr1 + 8192] still maps the file, it will take vma_merge_new_range to
expand the range, and then do uprobe_mmap in vma_complete. Since the
merged vma pgoff is also zero offset, it will install uprobe anon page to
the merged vma. However, the upcomming move_page_tables step, which use
set_pte_at to remap the vma2 uprobe pte to the merged vma, will overwrite
the newly uprobe pte in the merged vma, and lead that pte to be orphan.
Since the uprobe pte will be remapped to the merged vma, we can remove the
unnecessary uprobe_mmap upon merged vma.
This problem was first found in linux-6.6.y and also exists in the
community syzkaller:
https://lore.kernel.org/all/000000000000ada39605a5e71711@google.com/T/
Link: https://lkml.kernel.org/r/20250529155650.4017699-1-pulehui@huaweicloud.com
Link: https://lkml.kernel.org/r/20250529155650.4017699-2-pulehui@huaweicloud.com
Fixes:
|
||
|
Lorenzo Stoakes
|
3e43e260f1 |
mm: perform VMA allocation, freeing, duplication in mm
Right now these are performed in kernel/fork.c which is odd and a violation of separation of concerns, as well as preventing us from integrating this and related logic into userland VMA testing going forward. There is a fly in the ointment - nommu - mmap.c is not compiled if CONFIG_MMU not set, and neither is vma.c. To square the circle, let's add a new file - vma_init.c. This will be compiled for both CONFIG_MMU and nommu builds, and will also form part of the VMA userland testing. This allows us to de-duplicate code, while maintaining separation of concerns and the ability for us to userland test this logic. Update the VMA userland tests accordingly, additionally adding a detach_free_vma() helper function to correctly detach VMAs before freeing them in test code, as this change was triggering the assert for this. [akpm@linux-foundation.org: remove stray newline, per Liam] Link: https://lkml.kernel.org/r/f97b3a85a6da0196b28070df331b99e22b263be8.1745853549.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
dd7a6246f4 |
mm: abstract initial stack setup to mm subsystem
There are peculiarities within the kernel where what is very clearly mm code is performed elsewhere arbitrarily. This violates separation of concerns and makes it harder to refactor code to make changes to how fundamental initialisation and operation of mm logic is performed. One such case is the creation of the VMA containing the initial stack upon execve()'ing a new process. This is currently performed in __bprm_mm_init() in fs/exec.c. Abstract this operation to create_init_stack_vma(). This allows us to limit use of vma allocation and free code to fork and mm only. We previously did the same for the step at which we relocate the initial stack VMA downwards via relocate_vma_down(), now we move the initial VMA establishment too. Take the opportunity to also move insert_vm_struct() to mm/vma.c as it's no longer needed anywhere outside of mm. Link: https://lkml.kernel.org/r/118c950ef7a8dd19ab20a23a68c3603751acd30e.1745853549.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
6c36ac1e12 |
mm: establish mm/vma_exec.c for shared exec/mm VMA functionality
Patch series "move all VMA allocation, freeing and duplication logic to mm", v3. Currently VMA allocation, freeing and duplication exist in kernel/fork.c, which is a violation of separation of concerns, and leaves these functions exposed to the rest of the kernel when they are in fact internal implementation details. Resolve this by moving this logic to mm, and making it internal to vma.c, vma.h. This also allows us, in future, to provide userland testing around this functionality. We additionally abstract dup_mmap() to mm, being careful to ensure kernel/fork.c acceses this via the mm internal header so it is not exposed elsewhere in the kernel. As part of this change, also abstract initial stack allocation performed in __bprm_mm_init() out of fs code into mm via the create_init_stack_vma(), as this code uses vm_area_alloc() and vm_area_free(). In order to do so sensibly, we introduce a new mm/vma_exec.c file, which contains the code that is shared by mm and exec. This file is added to both memory mapping and exec sections in MAINTAINERS so both sets of maintainers can maintain oversight. As part of this change, we also move relocate_vma_down() to mm/vma_exec.c so all shared mm/exec functionality is kept in one place. We add code shared between nommu and mmu-enabled configurations in order to share VMA allocation, freeing and duplication code correctly while also keeping these functions available in userland VMA testing. This is achieved by adding a mm/vma_init.c file which is also compiled by the userland tests. This patch (of 4): There is functionality that overlaps the exec and memory mapping subsystems. While it properly belongs in mm, it is important that exec maintainers maintain oversight of this functionality correctly. We can establish both goals by adding a new mm/vma_exec.c file which contains these 'glue' functions, and have fs/exec.c import them. As a part of this change, to ensure that proper oversight is achieved, add the file to both the MEMORY MAPPING and EXEC & BINFMT API, ELF sections. scripts/get_maintainer.pl can correctly handle files in multiple entries and this neatly handles the cross-over. [akpm@linux-foundation.org: fix comment typo] Link: https://lkml.kernel.org/r/80f0d0c6-0b68-47f9-ab78-0ab7f74677fc@lucifer.local Link: https://lkml.kernel.org/r/cover.1745853549.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/91f2cee8f17d65214a9d83abb7011aa15f1ea690.1745853549.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
41e6ddcaa0 |
mm/vma: add give_up_on_oom option on modify/merge, use in uffd release
Currently, if a VMA merge fails due to an OOM condition arising on commit
merge or a failure to duplicate anon_vma's, we report this so the caller
can handle it.
However there are cases where the caller is only ostensibly trying a
merge, and doesn't mind if it fails due to this condition.
Since we do not want to introduce an implicit assumption that we only
actually modify VMAs after OOM conditions might arise, add a 'give up on
oom' option and make an explicit contract that, should this flag be set, we
absolutely will not modify any VMAs should OOM arise and just bail out.
Since it'd be very unusual for a user to try to vma_modify() with this flag
set but be specifying a range within a VMA which ends up being split (which
can fail due to rlimit issues, not only OOM), we add a debug warning for
this condition.
The motivating reason for this is uffd release - syzkaller (and Pedro
Falcato's VERY astute analysis) found a way in which an injected fault on
allocation, triggering an OOM condition on commit merge, would result in
uffd code becoming confused and treating an error value as if it were a VMA
pointer.
To avoid this, we make use of this new VMG flag to ensure that this never
occurs, utilising the fact that, should we be clearing entire VMAs, we do
not wish an OOM event to be reported to us.
Many thanks to Pedro Falcato for his excellent analysis and Jann Horn for
his insightful and intelligent analysis of the situation, both of whom were
instrumental in this fix.
Link: https://lkml.kernel.org/r/20250321100937.46634-1-lorenzo.stoakes@oracle.com
Reported-by: syzbot+20ed41006cf9d842c2b5@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67dc67f0.050a0220.25ae54.001e.GAE@google.com/
Fixes:
|
||
|
Suren Baghdasaryan
|
3104138517 |
mm: make vma cache SLAB_TYPESAFE_BY_RCU
To enable SLAB_TYPESAFE_BY_RCU for vma cache we need to ensure that object reuse before RCU grace period is over will be detected by lock_vma_under_rcu(). Current checks are sufficient as long as vma is detached before it is freed. The only place this is not currently happening is in exit_mmap(). Add the missing vma_mark_detached() in exit_mmap(). Another issue which might trick lock_vma_under_rcu() during vma reuse is vm_area_dup(), which copies the entire content of the vma into a new one, overriding new vma's vm_refcnt and temporarily making it appear as attached. This might trick a racing lock_vma_under_rcu() to operate on a reused vma if it found the vma before it got reused. To prevent this situation, we should ensure that vm_refcnt stays at detached state (0) when it is copied and advances to attached state only after it is added into the vma tree. Introduce vm_area_init_from() which preserves new vma's vm_refcnt and use it in vm_area_dup(). Since all vmas are in detached state with no current readers when they are freed, lock_vma_under_rcu() will not be able to take vm_refcnt after vma got detached even if vma is reused. vma_mark_attached() in modified to include a release fence to ensure all stores to the vma happen before vm_refcnt gets initialized. Finally, make vm_area_cachep SLAB_TYPESAFE_BY_RCU. This will facilitate vm_area_struct reuse and will minimize the number of call_rcu() calls. [surenb@google.com: remove atomic_set_release() usage in tools/] Link: https://lkml.kernel.org/r/20250217054351.2973666-1-surenb@google.com Link: https://lkml.kernel.org/r/20250213224655.1680278-18-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Shivank Garg <shivankg@amd.com> Link: https://lkml.kernel.org/r/5e19ec93-8307-47c2-bb13-3ddf7150624e@amd.com Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Klara Modin <klarasmodin@gmail.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Sourav Panda <souravpanda@google.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Suren Baghdasaryan
|
55e50223bf |
mm: introduce vma_iter_store_attached() to use with attached vmas
vma_iter_store() functions can be used both when adding a new vma and when updating an existing one. However for existing ones we do not need to mark them attached as they are already marked that way. With vma->detached being a separate flag, double-marking a vmas as attached or detached is not an issue because the flag will simply be overwritten with the same value. However once we fold this flag into the refcount later in this series, re-attaching or re-detaching a vma becomes an issue since these operations will be incrementing/decrementing a refcount. Introduce vma_iter_store_new() and vma_iter_store_overwrite() to replace vma_iter_store() and avoid re-attaching a vma during vma update. Add assertions in vma_mark_attached()/vma_mark_detached() to catch invalid usage. Update vma tests to check for vma detached state correctness. Link: https://lkml.kernel.org/r/20250213224655.1680278-5-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Tested-by: Shivank Garg <shivankg@amd.com> Link: https://lkml.kernel.org/r/5e19ec93-8307-47c2-bb13-3ddf7150624e@amd.com Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Klara Modin <klarasmodin@gmail.com> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Sourav Panda <souravpanda@google.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Suren Baghdasaryan
|
8ef95d8f15 |
mm: mark vma as detached until it's added into vma tree
Current implementation does not set detached flag when a VMA is first allocated. This does not represent the real state of the VMA, which is detached until it is added into mm's VMA tree. Fix this by marking new VMAs as detached and resetting detached flag only after VMA is added into a tree. Introduce vma_mark_attached() to make the API more readable and to simplify possible future cleanup when vma->vm_mm might be used to indicate detached vma and vma_mark_attached() will need an additional mm parameter. Link: https://lkml.kernel.org/r/20250213224655.1680278-4-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Tested-by: Shivank Garg <shivankg@amd.com> Link: https://lkml.kernel.org/r/5e19ec93-8307-47c2-bb13-3ddf7150624e@amd.com Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Klara Modin <klarasmodin@gmail.com> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Sourav Panda <souravpanda@google.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
0e5ffe9b2b |
mm: make vmg->target consistent and further simplify commit_merge()
It is confusing for vmg->target to sometimes be the target merged VMA and in one case not. Fix this by having commit_merge() use its awareness of the vmg->_adjust_next_start case to know that it is manipulating a separate vma, abstracted in the 'vma' local variable. Place removal and adjust VMA determination logic into init_multi_vma_prep(), as the flags give us enough information to do so, and since this is the function that sets up the vma_prepare struct it makes sense to do so here. Doing this significantly simplifies commit_merge(), allowing us to eliminate the 'merge_target' handling, initialise the VMA iterator in a more sensible place and simply return vmg->target consistently. This also allows us to simplify setting vmg->target in vma_merge_existing_range() since we are then left only with two cases - merge left (or both) where the target is vmg->prev or merge right in which the target is vmg->next. This makes it easy for somebody reading the code to know what VMA will actually be the one returned and merged into and removes a great deal of the confusing 'adjust' nonsense. This patch has no change in functional behaviour. Link: https://lkml.kernel.org/r/50f96e31ab1980eaaf1006e34a4f6e6dad9320b8.1738326519.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
fe3e9cf0d7 |
mm: eliminate adj_start parameter from commit_merge()
Introduce internal vmg->__adjust_middle_start and vmg->__adjust_next_start merge flags, enabling us to indicate to commit_merge() that we are performing a merge which either spans only part of vmg->middle, or part of vmg->next respectively. In the former instance, we change the start of vmg->middle to match the attributes of vmg->prev, without spanning all of vmg->middle. This implies that vmg->prev->vm_end and vmg->middle->vm_start are both increased to form the new merged VMA (vmg->prev) and the new subsequent VMA (vmg->middle). In the latter case, we change the end of vmg->middle to match the attributes of vmg->next, without spanning all of vmg->next. This implies that vmg->middle->vm_end and vmg->next->vm_start are both decreased to form the new merged VMA (vmg->next) and the new prior VMA (vmg->middle). Since we now have a stable set of prev, middle, next VMAs threaded through vmg and with these flags set know what is happening, we can perform the calculation in commit_merge() instead. This allows us to drop the confusing adj_start parameter and instead pass semantic information to commit_merge(). In the latter case the -(middle->vm_end - start) calculation becomes -(middle->vm-end - vmg->end), however this is correct as vmg->end is set to the start parameter. This is because in this case (rather confusingly), we manipulate vmg->middle, but ultimately return vmg->next, whose range will be correctly specified. At this point vmg->start, end is the new range for the prior VMA rather than the merged one. This patch has no change in functional behaviour. Link: https://lkml.kernel.org/r/bcec0cd980b373a5eb02236cb033034ce1effe42.1738326519.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
6ab2d9c7c6 |
mm: further refactor commit_merge()
The current VMA merge mechanism contains a number of confusing mechanisms around removal of VMAs on merge and the shrinking of the VMA adjacent to vma->target in the case of merges which result in a partial merge with that adjacent VMA. Since we now have a STABLE set of VMAs - prev, middle, next - we are now able to have the caller of commit_merge() explicitly tell us which VMAs need deleting, using newly introduced internal VMA merge flags. Doing so allows us to embed this state within the VMG and remove the confusing remove, remove2 parameters from commit_merge(). We additionally are able to eliminate the highly confusing and misleading 'expanded' parameter - a parameter that in reality refers to whether or not the return VMA is the target one or the one immediately adjacent. We can infer which is the case from whether or not the adj_start parameter is negative. This also allows us to simplify further logic around iterator configuration and VMA iterator stores. Doing so means we can also eliminate the adjust parameter, as we are able to infer which VMA ought to be adjusted from adj_start - a positive value implies we adjust the start of 'middle', a negative one implies we adjust the start of 'next'. We are then able to have commit_merge() explicitly return the target VMA, or NULL on inability to pre-allocate memory. Errors were previously filtered so behaviour does not change. We additionally move from the slightly odd use of a bitwise-flag enum vmg->merge_flags field to vmg bitfields. This patch has no change in functional behaviour. Link: https://lkml.kernel.org/r/7bf2ed24af68aac18672b7acebbd9102f48c5b03.1738326519.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
3a75ccba04 |
mm: simplify vma merge structure and expand comments
Patch series "mm: further simplify VMA merge operation", v3.
While significant efforts have been made to improve the VMA merge
operation, there remains remnants of the bad (or rather confusing) old
days, which make the code difficult to understand, more bug prone and thus
harder to modify.
This series attempts to significantly improve matters in a number of
respects - with a focus on simplifying the commit_merge() function which
actually actions the merge operation - and importantly, adjusting the two
most confusing merge cases - those in which we 'adjust' the VMA
immediately adjacent to the one being merged.
One source of confusion are the VMAs being threaded through the operation
themselves - vmg->prev, vmg->vma and vmg->next.
At the start of the operation, vmg->vma is either NULL if a new VMA is
propose to be added, or if not then a pointer to an existing VMA being
modified, and prev/next are (perhaps not present) VMAs sat immediately
before and after the range specified in vmg->start, end, respectively.
However, during the VMA merge operation, we change vmg->start, end and
pgoff to span the newly merged range and vmg->vma to either be:
a. The ultimately returned VMA (in most cases) or b. A VMA which we will
manipulate, but ultimately instead return vmg->next.
Case b. especially here is confusing for somebody reading this code, but
the fact we update this state, along with vmg->start, end, pgoff only
makes matters worse.
We simplify things by replacing vmg->vma with vmg->middle and never
changing it - this is always either NULL (for a new VMA) or the VMA being
modified between vmg->prev and vmg->next.
We further simplify by placing the merged VMA in a new vmg->target field -
whether case b. above is the case or not. The reader of the code can now
simply rely on vmg->middle being the middle VMA and vmg->target being the
ultimately merged VMA.
We additionally tackle the confusing cases where we 'adjust' VMAs other
than the one we ultimately return as the merged VMA (this includes case b.
above). These are:
(1)
merge
<----------->
|------||--------| |------------|---|
| prev || middle | -> | target | m |
|------||--------| |------------|---|
In which case middle must be adjusted so middle->vm_start is increased as
well as performing the merge.
(2) (equivalent to case b. above)
<------------->
|---------||------| |---|-------------|
| middle || next | -> | m | target |
|---------||------| |---|-------------|
In which case next must be adjusted so next->vm_start is decreased as well
as performing the merge.
This cases have previously been performed by calculating and passing
around a dubious and confusing 'adj_start' parameter along side a pointer
to an 'adjust' VMA indicating which VMA requires additional adjustment
(middle in case 1 and next in case 2).
With the VMG structure in place we are able to avoid this by simply
setting a merge flag to describe each case:
(1) Sets the vmg->__adjust_middle_start flag
(2) Sets the vmg->__adjust_next_start flag
By doing so it turns out we can vastly simplify the logic and calculate
what is required to perform the operation.
Taken together the refactorings make it far easier to understand what is
being done even in these more confusing cases, make the code far more
maintainable, debuggable, and testable, providing more internal state
indicating what is happening in the merge operation.
The changes have no functional net impact on the merge operation and
everything should still behave as it did before.
This patch (of 5):
The merge code, while much improved, still has a number of points of
confusion. As part of a broader series cleaning this up to make this more
maintainable, we start by addressing some confusion around
vma_merge_struct fields.
So far, the caller either provides no vmg->vma (a new VMA) or supplies the
existing VMA which is being altered, setting vmg->start,end,pgoff to the
proposed VMA dimensions.
vmg->vma is then updated, as are vmg->start,end,pgoff as the merge process
proceeds and the appropriate merge strategy is determined.
This is rather confusing, as vmg->vma starts off as the 'middle' VMA
between vmg->prev,next, but becomes the 'target' VMA, except in one
specific edge case (merge next, shrink middle).
Int his patch we introduce vmg->middle to describe the VMA that is between
vmg->prev and vmg->next, and does NOT change during the merge operation.
We replace vmg->vma with vmg->target, and use this only during the merge
operation itself.
Aside from the merge right, shrink middle case, this becomes the VMA that
forms the basis of the VMA that is returned. This edge case can be
addressed in a future commit.
We also add a number of comments to explain what is going on.
Finally, we adjust the ASCII diagrams showing each merge case in
vma_merge_existing_range() to be clearer - the arrow range previously
showed the vmg->start, end spanned area, but it is clearer to change this
to show the final merged VMA.
This patch has no change in functional behaviour.
Link: https://lkml.kernel.org/r/cover.1738326519.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/4dfe60f1419d55e5d0516f56349695d73a57184c.1738326519.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Lorenzo Stoakes
|
f8d4a6cabb |
mm: make mmap_region() internal
Now that we have removed the one user of mmap_region() outside of mm, make it internal and add it to vma.c so it can be userland tested. This ensures that all external memory mappings are performed using the appropriate interfaces and allows us to modify memory mapping logic as we see fit. Additionally expand test stubs to allow for the mmap_region() code to compile and be userland testable. Link: https://lkml.kernel.org/r/de5a3c574d35c26237edf20a1d8652d7305709c9.1735819274.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
24bd843b1d |
mm: enforce __must_check on VMA merge and split
It is of critical importance to check the return results on VMA merge (and split), failure to do so can result in use-after-free's. This bug has recurred, so have the compiler enforce this check to prevent any future repetition. Link: https://lkml.kernel.org/r/20241206225036.273103-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
bef5418d1f |
mm/vma: move __vm_munmap() to mm/vma.c
This was arbitrarily left in mmap.c it makes no sense being there, move it to vma.c to render it testable. Link: https://lkml.kernel.org/r/5e5e81807c54dfbe363edb2d431eb3d7a37fcdba.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
a9d1f3f2d7 |
mm/vma: move stack expansion logic to mm/vma.c
We build on previous work making expand_downwards() an entirely internal function. This logic is subtle and so it is highly useful to get it into vma.c so we can then userland unit test. We must additionally move acct_stack_growth() to vma.c as it is a helper function used by both expand_downwards() and expand_upwards(). We are also then able to mark anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma() static as these are no longer used by anything else. Link: https://lkml.kernel.org/r/0feb104eff85922019d4fb29280f3afb130c5204.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
c7c643d985 |
mm/vma: move unmapped_area() internals to mm/vma.c
We want to be able to unit test the unmapped area logic, so move it to mm/vma.c. The wrappers which invoke this remain in place in mm/mmap.c. In addition, naturally, update the existing test code to enable this to be compiled in userland. Link: https://lkml.kernel.org/r/53a57a52a64ea54e9d129d2e2abca3a538022379.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
7d344babac |
mm/vma: move brk() internals to mm/vma.c
Patch series "mm/vma: make more mmap logic userland testable".
This series carries on the work started in previous series and
continued in commit
|
||
|
Lorenzo Stoakes
|
52956b0d7f |
mm: isolate mmap internal logic to mm/vma.c
In previous commits we effected improvements to the mmap() logic in mmap_region() and its newly introduced internal implementation function __mmap_region(). However as these changes are intended to be backported, we kept the delta as small as is possible and made as few changes as possible to the newly introduced mm/vma.* files. Take the opportunity to move this logic to mm/vma.c which not only isolates it, but also makes it available for later userland testing which can help us catch such logic errors far earlier. Link: https://lkml.kernel.org/r/93fc2c3aa37dd30590b7e4ee067dfd832007bf7e.1729858176.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
0fb4a7ad27 |
mm: refactor map_deny_write_exec()
Refactor the map_deny_write_exec() to not unnecessarily require a VMA
parameter but rather to accept VMA flags parameters, which allows us to
use this function early in mmap_region() in a subsequent commit.
While we're here, we refactor the function to be more readable and add
some additional documentation.
Link: https://lkml.kernel.org/r/6be8bb59cd7c68006ebb006eb9d8dc27104b1f70.1730224667.git.lorenzo.stoakes@oracle.com
Fixes:
|
||
|
Lorenzo Stoakes
|
4080ef1579 |
mm: unconditionally close VMAs on error
Incorrect invocation of VMA callbacks when the VMA is no longer in a
consistent state is bug prone and risky to perform.
With regards to the important vm_ops->close() callback We have gone to
great lengths to try to track whether or not we ought to close VMAs.
Rather than doing so and risking making a mistake somewhere, instead
unconditionally close and reset vma->vm_ops to an empty dummy operations
set with a NULL .close operator.
We introduce a new function to do so - vma_close() - and simplify existing
vms logic which tracked whether we needed to close or not.
This simplifies the logic, avoids incorrect double-calling of the .close()
callback and allows us to update error paths to simply call vma_close()
unconditionally - making VMA closure idempotent.
Link: https://lkml.kernel.org/r/28e89dda96f68c505cb6f8e9fc9b57c3e9f74b42.1730224667.git.lorenzo.stoakes@oracle.com
Fixes:
|
||
|
Lorenzo Stoakes
|
c4d91e225f |
mm/vma: add expand-only VMA merge mode and optimise do_brk_flags()
Patch series "introduce VMA merge mode to improve brk() performance".
A ~5% performance regression was discovered on the
aim9.brk_test.ops_per_sec by the linux kernel test bot [0].
In the past to satisfy brk() performance we duplicated VMA expansion code
and special-cased do_brk_flags(). This is however horrid and undoes work
to abstract this logic, so in resolving the issue I have endeavoured to
avoid this.
Investigating further I was able to observe that the use of a
vma_iter_next_range() and vma_prev() pair, causing an unnecessary maple
tree walk. In addition there is work that we do that is simply
unnecessary for brk().
Therefore, add a special VMA merge mode VMG_FLAG_JUST_EXPAND to avoid
doing any of this - it assumes the VMA iterator is pointing at the
previous VMA and which skips logic that brk() does not require.
This mostly eliminates the performance regression reducing it to ~2% which
is in the realm of noise. In addition, the will-it-scale test brk2,
written to be more representative of real-world brk() usage, shows a
modest performance improvement - which gives me confidence that we are not
meaningfully regressing real workloads here.
This series includes a test asserting that the 'just expand' mode works as
expected.
With many thanks to Oliver Sang for helping with performance testing of
candidate patch sets!
[0]:https://lore.kernel.org/linux-mm/202409301043.629bea78-oliver.sang@intel.com
This patch (of 2):
We know in advance that do_brk_flags() wants only to perform a VMA
expansion (if the prior VMA is compatible), and that we assume no
mergeable VMA follows it.
These are the semantics of this function prior to the recent rewrite of
the VMA merging logic, however we are now doing more work than necessary -
positioning the VMA iterator at the prior VMA and performing tasks that
are not required.
Add a new field to the vmg struct to permit merge flags and add a new
merge flag VMG_FLAG_JUST_EXPAND which implies this behaviour, and have
do_brk_flags() use this.
This fixes a reported performance regression in a brk() benchmarking suite.
Link: https://lkml.kernel.org/r/cover.1729174352.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/4e65d4395e5841c5acf8470dbcb714016364fd39.1729174352.git.lorenzo.stoakes@oracle.com
Fixes:
|
||
|
Jann Horn
|
14611508cb |
mm: mark mas allocation in vms_abort_munmap_vmas as __GFP_NOFAIL
vms_abort_munmap_vmas() is a recovery path where, on entry, some VMAs have
already been torn down halfway (in a way we can't undo) but are still
present in the maple tree.
At this point, we *must* remove the VMAs from the VMA tree, otherwise we
get UAF.
Because removing VMA tree nodes can require memory allocation, the
existing code has an error path which tries to handle this by reattaching
the VMAs; but that can't be done safely.
A nicer way to fix it would probably be to preallocate enough maple tree
nodes for the removal before the point of no return, or something like
that; but for now, fix it the easy and kinda ugly way, by marking this
allocation __GFP_NOFAIL.
Link: https://lkml.kernel.org/r/20241016-fix-munmap-abort-v1-1-601c94b2240d@google.com
Fixes:
|
||
|
Lorenzo Stoakes
|
25d3925fa5 |
mm: make vma_prepare() and friends static and internal to vma.c
Now we have abstracted merge behaviour for new VMA ranges, we are able to render vma_prepare(), init_vma_prep(), vma_complete(), can_vma_merge_before() and can_vma_merge_after() static and internal to vma.c. These are internal implementation details of kernel VMA manipulation and merging mechanisms and thus should not be exposed. This also renders the functions userland testable. Link: https://lkml.kernel.org/r/7f7f1c34ce10405a6aab2714c505af3cf41b7851.1725040657.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Mark Brown <broonie@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
cacded5e42 |
mm: avoid using vma_merge() for new VMAs
Abstract vma_merge_new_vma() to use vma_merge_struct and rename the resultant function vma_merge_new_range() to be clear what the purpose of this function is - a new VMA is desired in the specified range, and we wish to see if it is possible to 'merge' surrounding VMAs into this range rather than having to allocate a new VMA. Note that this function uses vma_extend() exclusively, so adopts its requirement that the iterator point at or before the gap. We add an assert to this effect. This is as opposed to vma_merge_existing_range(), which will be introduced in a subsequent commit, and provide the same functionality for cases in which we are modifying an existing VMA. In mmap_region() and do_brk_flags() we open code scenarios where we prefer to use vma_expand() rather than invoke a full vma_merge() operation. Abstract this logic and eliminate all of the open-coding, and also use the same logic for all cases where we add new VMAs to, rather than ultimately use vma_merge(), rather use vma_expand(). Doing so removes duplication and simplifies VMA merging in all such cases, laying the ground for us to eliminate the merging of new VMAs in vma_merge() altogether. Also add the ability for the vmg to track state, and able to report errors, allowing for us to differentiate a failed merge from an inability to allocate memory in callers. This makes it far easier to understand what is happening in these cases avoiding confusion, bugs and allowing for future optimisation. Also introduce vma_iter_next_rewind() to allow for retrieval of the next, and (optionally) the prev VMA, rewinding to the start of the previous gap. Introduce are_anon_vmas_compatible() to abstract individual VMA anon_vma comparison for the case of merging on both sides where the anon_vma of the VMA being merged maybe compatible with prev and next, but prev and next's anon_vma's may not be compatible with each other. Finally also introduce can_vma_merge_left() / can_vma_merge_right() to check adjacent VMA compatibility and that they are indeed adjacent. Link: https://lkml.kernel.org/r/49d37c0769b6b9dc03b27fe4d059173832556392.1725040657.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Tested-by: Mark Brown <broonie@kernel.org> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
fc21959f74 |
mm: abstract vma_expand() to use vma_merge_struct
The purpose of the vmg is to thread merge state through functions and avoid egregious parameter lists. We expand this to vma_expand(), which is used for a number of merge cases. Accordingly, adjust its callers, mmap_region() and relocate_vma_down(), to use a vmg. An added purpose of this change is the ability in a future commit to perform all new VMA range merging using vma_expand(). Link: https://lkml.kernel.org/r/4bc8c9dbc9ca52452ef8e587b28fe555854ceb38.1725040657.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Mark Brown <broonie@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
2f1c6611b0 |
mm: introduce vma_merge_struct and abstract vma_merge(),vma_modify()
Rather than passing around huge numbers of parameters to numerous helper
functions, abstract them into a single struct that we thread through the
operation, the vma_merge_struct ('vmg').
Adjust vma_merge() and vma_modify() to accept this parameter, as well as
predicate functions can_vma_merge_before(), can_vma_merge_after(), and the
vma_modify_...() helper functions.
Also introduce VMG_STATE() and VMG_VMA_STATE() helper macros to allow for
easy vmg declaration.
We additionally remove the requirement that vma_merge() is passed a VMA
object representing the candidate new VMA. Previously it used this to
obtain the mm_struct, file and anon_vma properties of the proposed range
(a rather confusing state of affairs), which are now provided by the vmg
directly.
We also remove the pgoff calculation previously performed vma_modify(),
and instead calculate this in VMG_VMA_STATE() via the vma_pgoff_offset()
helper.
Link: https://lkml.kernel.org/r/a955aad09d81329f6fbeb636b2dd10cde7b73dab.1725040657.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Bert Karwatzki <spasswolf@web.de>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Liam R. Howlett
|
723e1e8b77 |
mm/vma.h: optimise vma_munmap_struct
The vma_munmap_struct has a hole of 4 bytes and pushes the struct to three
cachelines. Relocating the three booleans upwards allows for the struct
to only use two cachelines (as reported by pahole on amd64).
Before:
struct vma_munmap_struct {
struct vma_iterator * vmi; /* 0 8 */
struct vm_area_struct * vma; /* 8 8 */
struct vm_area_struct * prev; /* 16 8 */
struct vm_area_struct * next; /* 24 8 */
struct list_head * uf; /* 32 8 */
long unsigned int start; /* 40 8 */
long unsigned int end; /* 48 8 */
long unsigned int unmap_start; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
long unsigned int unmap_end; /* 64 8 */
int vma_count; /* 72 4 */
/* XXX 4 bytes hole, try to pack */
long unsigned int nr_pages; /* 80 8 */
long unsigned int locked_vm; /* 88 8 */
long unsigned int nr_accounted; /* 96 8 */
long unsigned int exec_vm; /* 104 8 */
long unsigned int stack_vm; /* 112 8 */
long unsigned int data_vm; /* 120 8 */
/* --- cacheline 2 boundary (128 bytes) --- */
bool unlock; /* 128 1 */
bool clear_ptes; /* 129 1 */
bool closed_vm_ops; /* 130 1 */
/* size: 136, cachelines: 3, members: 19 */
/* sum members: 127, holes: 1, sum holes: 4 */
/* padding: 5 */
/* last cacheline: 8 bytes */
};
After:
struct vma_munmap_struct {
struct vma_iterator * vmi; /* 0 8 */
struct vm_area_struct * vma; /* 8 8 */
struct vm_area_struct * prev; /* 16 8 */
struct vm_area_struct * next; /* 24 8 */
struct list_head * uf; /* 32 8 */
long unsigned int start; /* 40 8 */
long unsigned int end; /* 48 8 */
long unsigned int unmap_start; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
long unsigned int unmap_end; /* 64 8 */
int vma_count; /* 72 4 */
bool unlock; /* 76 1 */
bool clear_ptes; /* 77 1 */
bool closed_vm_ops; /* 78 1 */
/* XXX 1 byte hole, try to pack */
long unsigned int nr_pages; /* 80 8 */
long unsigned int locked_vm; /* 88 8 */
long unsigned int nr_accounted; /* 96 8 */
long unsigned int exec_vm; /* 104 8 */
long unsigned int stack_vm; /* 112 8 */
long unsigned int data_vm; /* 120 8 */
/* size: 128, cachelines: 2, members: 19 */
/* sum members: 127, holes: 1, sum holes: 1 */
};
Link: https://lkml.kernel.org/r/20240830040101.822209-22-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Bert Karwatzki <spasswolf@web.de>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Liam R. Howlett
|
224c1c702c |
mm: move may_expand_vm() check in mmap_region()
The may_expand_vm() check requires the count of the pages within the munmap range. Since this is needed for accounting and obtained later, the reodering of ma_expand_vm() to later in the call stack, after the vma munmap struct (vms) is initialised and the gather stage is potentially run, will allow for a single loop over the vmas. The gather sage does not commit any work and so everything can be undone in the case of a failure. The MAP_FIXED page count is available after the vms_gather_munmap_vmas() call, so use it instead of looping over the vmas twice. Link: https://lkml.kernel.org/r/20240830040101.822209-20-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mark Brown <broonie@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Liam R. Howlett
|
63fc66f5b6 |
ipc/shm, mm: drop do_vma_munmap()
The do_vma_munmap() wrapper existed for callers that didn't have a vma iterator and needed to check the vma mseal status prior to calling the underlying munmap(). All callers now use a vma iterator and since the mseal check has been moved to do_vmi_align_munmap() and the vmas are aligned, this function can just be called instead. do_vmi_align_munmap() can no longer be static as ipc/shm is using it and it is exported via the mm.h header. Link: https://lkml.kernel.org/r/20240830040101.822209-19-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mark Brown <broonie@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Liam R. Howlett
|
4f87153e82 |
mm: change failure of MAP_FIXED to restoring the gap on failure
Prior to call_mmap(), the vmas that will be replaced need to clear the way for what may happen in the call_mmap(). This clean up work includes clearing the ptes and calling the close() vm_ops. Some users do more setup than can be restored by calling the vm_ops open() function. It is safer to store the gap in the vma tree in these cases. That is to say that the failure scenario that existed before the MAP_FIXED gap exposure is restored as it is safer than trying to undo a partial mapping. Since abort_munmap_vmas() is only reattaching vmas with this change, the function is renamed to reattach_vmas(). There is also a secondary failure that may occur if there is not enough memory to store the gap. In this case, the vmas are reattached and resources freed. If the system cannot complete the call_mmap() and fails to allocate with GFP_KERNEL, then the system will print a warning about the failure. [lorenzo.stoakes@oracle.com: fix off-by-one error in vms_abort_munmap_vmas()] Link: https://lkml.kernel.org/r/52ee7eb3-955c-4ade-b5f0-28fed8ba3d0b@lucifer.local Link: https://lkml.kernel.org/r/20240830040101.822209-16-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mark Brown <broonie@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |