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| author | Nhat Pham <nphamcs@gmail.com> | 2024-06-27 13:17:37 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-11-24 10:30:14 +0100 |
| commit | e2f7c76758be16f1dc32c5a82270d4f6649eedab (patch) | |
| tree | 856c21454c9d8ec8d32c8795546e85ff48779901 /mm/filemap.c | |
| parent | 1f45e5c84684bc10c83013517b2b948e41b890d0 (diff) | |
| download | linux-e2f7c76758be16f1dc32c5a82270d4f6649eedab.tar.gz linux-e2f7c76758be16f1dc32c5a82270d4f6649eedab.tar.bz2 linux-e2f7c76758be16f1dc32c5a82270d4f6649eedab.zip | |
cachestat: do not flush stats in recency check
commit 5a4d8944d6b1e1aaaa83ea42c116b520b4ed0394 upstream.
syzbot detects that cachestat() is flushing stats, which can sleep, in its
RCU read section (see [1]). This is done in the workingset_test_recent()
step (which checks if the folio's eviction is recent).
Move the stat flushing step to before the RCU read section of cachestat,
and skip stat flushing during the recency check.
[1]: https://lore.kernel.org/cgroups/000000000000f71227061bdf97e0@google.com/
Link: https://lkml.kernel.org/r/20240627201737.3506959-1-nphamcs@gmail.com
Fixes: b00684722262 ("mm: workingset: move the stats flush into workingset_test_recent()")
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Reported-by: syzbot+b7f13b2d0cc156edf61a@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/cgroups/000000000000f71227061bdf97e0@google.com/
Debugged-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: <stable@vger.kernel.org> [6.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 6e01364a1ca6..1c229b261a62 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -4210,6 +4210,9 @@ static void filemap_cachestat(struct address_space *mapping, XA_STATE(xas, &mapping->i_pages, first_index); struct folio *folio; + /* Flush stats (and potentially sleep) outside the RCU read section. */ + mem_cgroup_flush_stats_ratelimited(NULL); + rcu_read_lock(); xas_for_each(&xas, folio, last_index) { int order; @@ -4273,7 +4276,7 @@ static void filemap_cachestat(struct address_space *mapping, goto resched; } #endif - if (workingset_test_recent(shadow, true, &workingset)) + if (workingset_test_recent(shadow, true, &workingset, false)) cs->nr_recently_evicted += nr_pages; goto resched; |