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cachefiles: fix memory leak in cachefiles_add_cache()

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The following memory leak was reported after unbinding /dev/cachefiles:

==================================================================
unreferenced object 0xffff9b674176e3c0 (size 192):
  comm "cachefilesd2", pid 680, jiffies 4294881224
  hex dump (first 32 bytes):
    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc ea38a44b):
    [<ffffffff8eb8a1a5>] kmem_cache_alloc+0x2d5/0x370
    [<ffffffff8e917f86>] prepare_creds+0x26/0x2e0
    [<ffffffffc002eeef>] cachefiles_determine_cache_security+0x1f/0x120
    [<ffffffffc00243ec>] cachefiles_add_cache+0x13c/0x3a0
    [<ffffffffc0025216>] cachefiles_daemon_write+0x146/0x1c0
    [<ffffffff8ebc4a3b>] vfs_write+0xcb/0x520
    [<ffffffff8ebc5069>] ksys_write+0x69/0xf0
    [<ffffffff8f6d4662>] do_syscall_64+0x72/0x140
    [<ffffffff8f8000aa>] entry_SYSCALL_64_after_hwframe+0x6e/0x76
==================================================================

Put the reference count of cache_cred in cachefiles_daemon_unbind() to
fix the problem. And also put cache_cred in cachefiles_add_cache() error
branch to avoid memory leaks.

Fixes: 9ae326a690 ("CacheFiles: A cache that backs onto a mounted filesystem")
CC: stable@vger.kernel.org
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240217081431.796809-1-libaokun1@huawei.com
Acked-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Baokun Li 2024-02-17 16:14:31 +08:00 committed by Christian Brauner
parent ca9ca1a5d5
commit e21a2f1756
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GPG Key ID: 91C61BC06578DCA2
2 changed files with 3 additions and 0 deletions
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2
fs/cachefiles/cache.c
View File

@ -168,6 +168,8 @@ error_unsupported:
dput(root);
error_open_root:
cachefiles_end_secure(cache, saved_cred);
put_cred(cache->cache_cred);
cache->cache_cred = NULL;
error_getsec:
fscache_relinquish_cache(cache_cookie);
cache->cache = NULL;

1
fs/cachefiles/daemon.c
View File

@ -816,6 +816,7 @@ static void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
cachefiles_put_directory(cache->graveyard);
cachefiles_put_directory(cache->store);
mntput(cache->mnt);
put_cred(cache->cache_cred);
kfree(cache->rootdirname);
kfree(cache->secctx);