From: Jan Kara Date: Tue, 31 Oct 2017 08:53:28 +0000 (+0100) Subject: dnotify: Handle errors from fsnotify_add_mark_locked() in fcntl_dirnotify() X-Git-Tag: 4.15-smb3-updates~123^2~9 X-Git-Url: http://git.samba.org/samba.git/?p=sfrench%2Fcifs-2.6.git;a=commitdiff_plain;h=b3a0066005821acdc0cdb092cb72587182ab583f dnotify: Handle errors from fsnotify_add_mark_locked() in fcntl_dirnotify() 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 Reported-by: syzkaller Fixes: 9dd813c15b2c101168808d4f5941a29985758973 Signed-off-by: Jan Kara --- diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index cba328315929..63a1ca4b9dee 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -319,7 +319,11 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) 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 *filp, unsigned long arg) */ if (dn_mark == new_dn_mark) destroy = 1; + error = 0; goto out; }