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mm: /proc/pid/smaps_rollup: avoid skipping vma after getting mmap_lock again

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After switching smaps_rollup to use VMA iterator, searching for next entry
is part of the condition expression of the do-while loop.  So the current
VMA needs to be addressed before the continue statement.

Otherwise, with some VMAs skipped, userspace observed memory
consumption from /proc/pid/smaps_rollup will be smaller than the sum of
the corresponding fields from /proc/pid/smaps.

Link: https://lkml.kernel.org/r/20240523183531.2535436-1-yzhong@purestorage.com
Fixes: c4c84f0628 ("fs/proc/task_mmu: stop using linked list and highest_vm_end")
Signed-off-by: Yuanyuan Zhong <yzhong@purestorage.com>
Reviewed-by: Mohamed Khalfella <mkhalfella@purestorage.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Yuanyuan Zhong 2024-05-23 12:35:31 -06:00 committed by Andrew Morton
parent eb85dace89
commit 6d065f507d
1 changed files with 7 additions and 2 deletions
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9
fs/proc/task_mmu.c
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@ -970,12 +970,17 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
break;
/* Case 1 and 2 above */
if (vma->vm_start >= last_vma_end)
if (vma->vm_start >= last_vma_end) {
smap_gather_stats(vma, &mss, 0);
last_vma_end = vma->vm_end;
continue;
}
/* Case 4 above */
if (vma->vm_end > last_vma_end)
if (vma->vm_end > last_vma_end) {
smap_gather_stats(vma, &mss, last_vma_end);
last_vma_end = vma->vm_end;
}
}
} for_each_vma(vmi, vma);