From 6d065f507d82307d6161ac75c025111fb8b08a46 Mon Sep 17 00:00:00 2001
From: Yuanyuan Zhong <yzhong@purestorage.com>
Date: Thu, 23 May 2024 12:35:31 -0600
Subject: [PATCH] mm: /proc/pid/smaps_rollup: avoid skipping vma after getting
mmap_lock again
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: c4c84f06285e ("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>
---
fs/proc/task_mmu.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index e5a5f015ff03b..f8d35f993fe50 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -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);
--
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