cachefiles: fix memory leak in cachefiles_add_cache()
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: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem")
CC: [email protected]
Signed-off-by: Baokun Li <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Acked-by: David Howells <[email protected]>
Reviewed-by: Jingbo Xu <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
diff --git a/fs/cachefiles/cache.c b/fs/cachefiles/cache.c
index 7077f72..f449f73 100644
--- a/fs/cachefiles/cache.c
+++ b/fs/cachefiles/cache.c
@@ -168,6 +168,8 @@ int cachefiles_add_cache(struct cachefiles_cache *cache)
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;
