4.14-stable review patch. If anyone has any objections, please let me know.
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From: Jan Kara jack@suse.cz
commit b3a0066005821acdc0cdb092cb72587182ab583f upstream.
fsnotify_add_mark_locked() can fail but we do not check its return value. This didn't matter before commit 9dd813c15b2c "fsnotify: Move mark list head from object into dedicated structure" as none of possible failures could happen for dnotify but after that commit -ENOMEM can be returned. Handle this error properly in fcntl_dirnotify() as otherwise we just hit BUG_ON(dn_mark->dn) in dnotify_free_mark().
Reviewed-by: Amir Goldstein amir73il@gmail.com Reported-by: syzkaller Fixes: 9dd813c15b2c101168808d4f5941a29985758973 Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/notify/dnotify/dnotify.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -319,7 +319,11 @@ int fcntl_dirnotify(int fd, struct file dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark); spin_lock(&fsn_mark->lock); } else { - fsnotify_add_mark_locked(new_fsn_mark, inode, NULL, 0); + error = fsnotify_add_mark_locked(new_fsn_mark, inode, NULL, 0); + if (error) { + mutex_unlock(&dnotify_group->mark_mutex); + goto out_err; + } spin_lock(&new_fsn_mark->lock); fsn_mark = new_fsn_mark; dn_mark = new_dn_mark; @@ -345,6 +349,7 @@ int fcntl_dirnotify(int fd, struct file */ if (dn_mark == new_dn_mark) destroy = 1; + error = 0; goto out; }