diff options
| author | Oscar Salvador | 2024-05-28 22:53:23 +0200 |
|---|---|---|
| committer | Andrew Morton | 2024-06-05 19:19:26 -0700 |
| commit | 8daf9c702ee7f825f0de8600abff764acfedea13 (patch) | |
| tree | 85e566f73d554ad7a37e1054b02b3f0ed7aa9e14 /mm | |
| parent | c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 (diff) | |
mm/hugetlb: do not call vma_add_reservation upon ENOMEM
sysbot reported a splat [1] on __unmap_hugepage_range(). This is because
vma_needs_reservation() can return -ENOMEM if
allocate_file_region_entries() fails to allocate the file_region struct
for the reservation.
Check for that and do not call vma_add_reservation() if that is the case,
otherwise region_abort() and region_del() will see that we do not have any
file_regions.
If we detect that vma_needs_reservation() returned -ENOMEM, we clear the
hugetlb_restore_reserve flag as if this reservation was still consumed, so
free_huge_folio() will not increment the resv count.
[1] https://lore.kernel.org/linux-mm/0000000000004096100617c58d54@google.com/T/#ma5983bc1ab18a54910da83416b3f89f3c7ee43aa
Link: https://lkml.kernel.org/r/20240528205323.20439-1-osalvador@suse.de
Fixes: df7a6d1f6405 ("mm/hugetlb: restore the reservation if needed")
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reported-and-tested-by: syzbot+d3fe2dc5ffe9380b714b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/0000000000004096100617c58d54@google.com/
Cc: Breno Leitao <leitao@debian.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/hugetlb.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 6be78e7d4f6e..f35abff8be60 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5768,8 +5768,20 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, * do_exit() will not see it, and will keep the reservation * forever. */ - if (adjust_reservation && vma_needs_reservation(h, vma, address)) - vma_add_reservation(h, vma, address); + if (adjust_reservation) { + int rc = vma_needs_reservation(h, vma, address); + + if (rc < 0) + /* Pressumably allocate_file_region_entries failed + * to allocate a file_region struct. Clear + * hugetlb_restore_reserve so that global reserve + * count will not be incremented by free_huge_folio. + * Act as if we consumed the reservation. + */ + folio_clear_hugetlb_restore_reserve(page_folio(page)); + else if (rc) + vma_add_reservation(h, vma, address); + } tlb_remove_page_size(tlb, page, huge_page_size(h)); /* |