From: David Howells dhowells@redhat.com
mainline inclusion from mainline-v6.8-rc2 commit c3d6569a43322f371e7ba0ad386112723757ac8f category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I955IG
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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cachefiles_ondemand_init_object() as called from cachefiles_open_file() and cachefiles_create_tmpfile() does not check if object->ondemand is set before dereferencing it, leading to an oops something like:
RIP: 0010:cachefiles_ondemand_init_object+0x9/0x41 ... Call Trace: <TASK> cachefiles_open_file+0xc9/0x187 cachefiles_lookup_cookie+0x122/0x2be fscache_cookie_state_machine+0xbe/0x32b fscache_cookie_worker+0x1f/0x2d process_one_work+0x136/0x208 process_scheduled_works+0x3a/0x41 worker_thread+0x1a2/0x1f6 kthread+0xca/0xd2 ret_from_fork+0x21/0x33
Fix this by making cachefiles_ondemand_init_object() return immediately if cachefiles->ondemand is NULL.
Fixes: 3c5ecfe16e76 ("cachefiles: extract ondemand info field from cachefiles_object") Reported-by: Marc Dionne marc.dionne@auristor.com Signed-off-by: David Howells dhowells@redhat.com cc: Gao Xiang xiang@kernel.org cc: Chao Yu chao@kernel.org cc: Yue Hu huyue2@coolpad.com cc: Jeffle Xu jefflexu@linux.alibaba.com cc: linux-erofs@lists.ozlabs.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Baokun Li libaokun1@huawei.com --- fs/cachefiles/ondemand.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index 0254ed39f68c..3417975ab5fd 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -479,6 +479,9 @@ int cachefiles_ondemand_init_object(struct cachefiles_object *object) struct fscache_volume *volume = object->volume->vcookie; size_t volume_key_size, cookie_key_size, data_len;
+ if (!object->ondemand) + return 0; + /* * CacheFiles will firstly check the cache file under the root cache * directory. If the coherency check failed, it will fallback to