diff options
| author | Johannes Weiner <hannes@cmpxchg.org> | 2024-01-29 20:34:38 -0500 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-02-07 21:20:35 -0800 |
| commit | 2e601e1e8e4b330020a346c55ba111d49e0b188e (patch) | |
| tree | 7516700287f584302bb93ce534f3b67df5405b7d /mm | |
| parent | 4c2da3188b848d33c26d7f0f8b14f3150331c923 (diff) | |
mm: zswap: fix objcg use-after-free in entry destruction
In the per-memcg LRU universe, LRU removal uses entry->objcg to determine
which list count needs to be decreased. Drop the objcg reference after
updating the LRU, to fix a possible use-after-free.
Link: https://lkml.kernel.org/r/20240130013438.565167-1-hannes@cmpxchg.org
Fixes: a65b0e7607cc ("zswap: make shrinking memcg-aware")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/zswap.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/zswap.c b/mm/zswap.c index ca25b676048e..0a94b197ed32 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -536,10 +536,6 @@ static struct zpool *zswap_find_zpool(struct zswap_entry *entry) */ static void zswap_free_entry(struct zswap_entry *entry) { - if (entry->objcg) { - obj_cgroup_uncharge_zswap(entry->objcg, entry->length); - obj_cgroup_put(entry->objcg); - } if (!entry->length) atomic_dec(&zswap_same_filled_pages); else { @@ -548,6 +544,10 @@ static void zswap_free_entry(struct zswap_entry *entry) atomic_dec(&entry->pool->nr_stored); zswap_pool_put(entry->pool); } + if (entry->objcg) { + obj_cgroup_uncharge_zswap(entry->objcg, entry->length); + obj_cgroup_put(entry->objcg); + } zswap_entry_cache_free(entry); atomic_dec(&zswap_stored_pages); zswap_update_total_size(); |