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| author | Lorenzo Stoakes <lorenzo.stoakes@oracle.com> | 2024-10-29 18:11:45 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-11-05 16:49:55 -0800 |
| commit | 4080ef1579b2413435413988d14ac8c68e4d42c8 (patch) | |
| tree | d9d6e962c8f1ef1803f24af52332245190ddc3db /mm/mmap.c | |
| parent | 3dd6ed34ce1f2356a77fb88edafb5ec96784e3cf (diff) | |
| download | lwn-4080ef1579b2413435413988d14ac8c68e4d42c8.tar.gz lwn-4080ef1579b2413435413988d14ac8c68e4d42c8.zip | |
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: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: Jann Horn <jannh@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Jann Horn <jannh@google.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 6e3b25f7728f..ac0604f146f6 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1573,8 +1573,7 @@ expanded: return addr; close_and_free_vma: - if (file && !vms.closed_vm_ops && vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (file || vma->vm_file) { unmap_and_free_vma: @@ -1934,7 +1933,7 @@ void exit_mmap(struct mm_struct *mm) do { if (vma->vm_flags & VM_ACCOUNT) nr_accounted += vma_pages(vma); - remove_vma(vma, /* unreachable = */ true, /* closed = */ false); + remove_vma(vma, /* unreachable = */ true); count++; cond_resched(); vma = vma_next(&vmi); |