github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-28 18:21:24 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

mm/vmalloc: use physical page count for vrealloc() grow-in-place check

Browse Source 
Update the grow-in-place check in vrealloc() to compare the requested size
against the actual physical page count (vm->nr_pages) rather than the
virtual area size (alloced_size, derived from get_vm_area_size()).

Currently both values are equivalent, but the upcoming vrealloc() shrink
functionality will free pages without reducing the virtual reservation
size.  After such a shrink, the old alloced_size-based comparison would
incorrectly allow a grow-in-place operation to succeed and attempt to
access freed pages.  Switch to vm->nr_pages now so the check remains
correct once shrink support is added.

Link: https://lore.kernel.org/20260519-vmalloc-shrink-v14-2-70b96ee3e9c9@zohomail.in
Signed-off-by: Shivam Kalra <shivamkalra98@zohomail.in>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Shivam Kalra 2026-05-19 17:42:15 +05:30 committed by Andrew Morton
parent 4f1839e225
commit d57ac904ff
1 changed files with 7 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
mm/vmalloc.c
View File

@ -4343,6 +4343,12 @@ void *vrealloc_node_align_noprof(const void *p, size_t size, unsigned long align
if (unlikely(flags & __GFP_THISNODE) && nid != NUMA_NO_NODE &&
nid != page_to_nid(vmalloc_to_page(p)))
goto need_realloc;
} else {
/*
* If p is NULL, vrealloc behaves exactly like vmalloc.
* Skip the shrink and in-place grow paths.
*/
goto need_realloc;
}
/*
@ -4361,7 +4367,7 @@ void *vrealloc_node_align_noprof(const void *p, size_t size, unsigned long align
/*
* We already have the bytes available in the allocation; use them.
*/
if (size <= alloced_size) {
if (size <= vm->nr_pages << PAGE_SHIFT) {
/*
* No need to zero memory here, as unused memory will have
* already been zeroed at initial allocation time or during