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Linux kernel source tree
a0a9f2180b
I found a NULL pointer dereference as followed:
BUG: kernel NULL pointer dereference, address: 0000000000000028
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 5 UID: 0 PID: 5964 Comm: sh Kdump: loaded Not tainted 6.13.0-dirty #20
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.
RIP: 0010:has_unmovable_pages+0x184/0x360
...
Call Trace:
<TASK>
set_migratetype_isolate+0xd1/0x180
start_isolate_page_range+0xd2/0x170
alloc_contig_range_noprof+0x101/0x660
alloc_contig_pages_noprof+0x238/0x290
alloc_gigantic_folio.isra.0+0xb6/0x1f0
only_alloc_fresh_hugetlb_folio.isra.0+0xf/0x60
alloc_pool_huge_folio+0x80/0xf0
set_max_huge_pages+0x211/0x490
__nr_hugepages_store_common+0x5f/0xe0
nr_hugepages_store+0x77/0x80
kernfs_fop_write_iter+0x118/0x200
vfs_write+0x23c/0x3f0
ksys_write+0x62/0xe0
do_syscall_64+0x5b/0x170
entry_SYSCALL_64_after_hwframe+0x76/0x7e
As has_unmovable_pages() call folio_hstate() without hugetlb_lock, there
is a race to free the HugeTLB page between PageHuge() and folio_hstate().
There is no need to add hugetlb_lock here as the HugeTLB page can be freed
in lot of places. So it's enough to unfold folio_hstate() and add a check
to avoid NULL pointer dereference for hugepage_migration_supported().
Link: https://lkml.kernel.org/r/20250122061151.578768-1-liushixin2@huawei.com
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.