diff options
| author | Johannes Weiner <hannes@cmpxchg.org> | 2023-10-06 19:00:24 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-10-18 22:12:40 +0300 |
| commit | 969d63e1af3b3abe35a49b08218f3125131ac32f (patch) | |
| tree | 9795ec5405ccfeeec191bdfc7689caa9d30e567e | |
| parent | 229e2253766c7cdfe024f1fe280020cc4711087c (diff) | |
| download | linux-969d63e1af3b3abe35a49b08218f3125131ac32f.tar.xz | |
mm: zswap: fix pool refcount bug around shrink_worker()
When a zswap store fails due to the limit, it acquires a pool reference
and queues the shrinker. When the shrinker runs, it drops the reference.
However, there can be multiple store attempts before the shrinker wakes up
and runs once. This results in reference leaks and eventual saturation
warnings for the pool refcount.
Fix this by dropping the reference again when the shrinker is already
queued. This ensures one reference per shrinker run.
Link: https://lkml.kernel.org/r/20231006160024.170748-1-hannes@cmpxchg.org
Fixes: 45190f01dd40 ("mm/zswap.c: add allocation hysteresis if pool limit is hit")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Chris Mason <clm@fb.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: <stable@vger.kernel.org> [5.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/zswap.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/zswap.c b/mm/zswap.c index 083c693602b8..37d2b1cb2ecb 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1383,8 +1383,8 @@ reject: shrink: pool = zswap_pool_last_get(); - if (pool) - queue_work(shrink_wq, &pool->shrink_work); + if (pool && !queue_work(shrink_wq, &pool->shrink_work)) + zswap_pool_put(pool); goto reject; } |