Commit e5a6b3fe authored by Baokun Li's avatar Baokun Li
Browse files

cachefiles: fix memory leak in cachefiles_add_cache() 

mainline inclusion
from mainline-v6.8-rc6
commit e21a2f17566cbd64926fb8f16323972f7a064444
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I955OO

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e21a2f17566cbd64926fb8f16323972f7a064444



--------------------------------

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: 9ae326a6 ("CacheFiles: A cache that backs onto a mounted filesystem")
CC: stable@vger.kernel.org
Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240217081431.796809-1-libaokun1@huawei.com


Acked-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarJingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
parent 3016126e

fs/cachefiles/cache.c

+2 −0
Original line number Diff line number Diff line
@@ -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;

fs/cachefiles/daemon.c

+1 −0
Original line number Diff line number Diff line
@@ -805,6 +805,7 @@ 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);