On Mon, Jul 08, 2019 at 12:37:06PM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: d58b5ab9 Add linux-next specific files for 20190708 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=123d6887a00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=bf9882946ecc11d9 > dashboard link: https://syzkaller.appspot.com/bug?extid=f70e9b00f8c7d4187bd0 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=173375c7a00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1536f9bfa00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+f70e9b00f8c7d4187bd0@xxxxxxxxxxxxxxxxxxxxxxxxx > > ------------[ cut here ]------------ > kernel BUG at lib/lockref.c:189! Mea culpa... It's "Teach shrink_dcache_parent() to cope with mixed-filesystem shrink lists", and the fix should be simply this: diff --git a/fs/dcache.c b/fs/dcache.c index d8732cf2e302..d85d8f2c8c97 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1555,6 +1555,7 @@ void shrink_dcache_parent(struct dentry *parent) d_walk(parent, &data, select_collect2); if (data.victim) { struct dentry *parent; + spin_lock(&data.victim->d_lock); if (!shrink_lock_dentry(data.victim)) { rcu_read_unlock(); } else {
