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authorLinus Torvalds <torvalds@linux-foundation.org>2023-07-04 05:29:48 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2023-07-04 17:22:59 +0300
commitb5641a5d8b8b14643bfe3d017d64da90a5c55479 (patch)
tree9e5bd4006f597e073a4faa653b83185dcfa58534 /mm
parent24be4d0b46bb0c3c1dc7bacd30957d6144a70dfc (diff)
downloadlinux-b5641a5d8b8b14643bfe3d017d64da90a5c55479.tar.xz
mm: don't do validate_mm() unnecessarily and without mmap locking
This is an addition to commit ae80b4041984 ("mm: validate the mm before dropping the mmap lock"), because it turns out there were two problems, but lockdep just stopped complaining after finding the first one. The do_vmi_align_munmap() function now drops the mmap lock after doing the validate_mm() call, but it turns out that one of the callers then immediately calls validate_mm() again. That's both a bit silly, and now (again) happens without the mmap lock held. So just remove that validate_mm() call from the caller, but make sure to not lose any coverage by doing that mm sanity checking in the error path of do_vmi_align_munmap() too. Reported-and-tested-by: kernel test robot <oliver.sang@intel.com> Link: https://lore.kernel.org/lkml/ZKN6CdkKyxBShPHi@xsang-OptiPlex-9020/ Fixes: 408579cd627a ("mm: Update do_vmi_align_munmap() return semantics") Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mmap.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 547b40531791..204ddcd52625 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2571,6 +2571,7 @@ end_split_failed:
__mt_destroy(&mt_detach);
start_split_failed:
map_count_exceeded:
+ validate_mm(mm);
return error;
}
@@ -3019,12 +3020,9 @@ int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
bool unlock)
{
struct mm_struct *mm = vma->vm_mm;
- int ret;
arch_unmap(mm, start, end);
- ret = do_vmi_align_munmap(vmi, vma, mm, start, end, uf, unlock);
- validate_mm(mm);
- return ret;
+ return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, unlock);
}
/*