Re: INFO: trying to register non-static key in rhashtable_walk_enter

On 2019/5/19 4:12, David Miller wrote:

From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: Sat, 18 May 2019 14:19:07 -0400

quoted

On Sat, May 18, 2019 at 2:09 PM Willem de Bruijn
[off-list ref] wrote:

quoted

On Sat, May 18, 2019 at 3:34 AM syzbot
[off-list ref] wrote:

quoted

Hello,

syzbot found the following crash on:

HEAD commit:    510e2ced ipv6: fix src addr routing with the exception table
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=15b7e608a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=82f0809e8f0a8c87
dashboard link: https://syzkaller.appspot.com/bug?extid=1e8114b61079bfe9cbc5
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1e8114b61079bfe9cbc5@syzkaller.appspotmail.com

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.

All these five rhashtable_walk_enter probably have the same root cause.

Bisected to commit 7e27e8d6130c (" tipc: switch order of device
registration to fix a crash"). Reverting that fixes it.

Before the commit, tipc_init succeeds. After the commit it fails at
register_pernet_subsys(&tipc_net_ops) due to error in

  tipc_init_net
    tipc_topsrv_start
      tipc_topsrv_create_listener
        sock_create_kern

On a related note, in tipc_topsrv_start srv is also not freed on later
error paths.

and tipc_topsrv_stop is not called in tipc_init_net on later error paths.

This was gonna get fixed by:

532b0f7ece4cb2ffd24dc723ddf55242d1188e5e
tipc: fix modprobe tipc failed after switch order of device registration

I think...

But I reverted because they were still fiddling around with the fix.

This looks really bad at this point and I'm likely to revert 7e27e8d6130c
because it creates so many more bugs than it fixes :-////

.

Hi, David
I am really sorry for this, just as you said, this bug fixed by:
532b0f7ece4cb2ffd24dc723ddf55242d1188e5e
tipc: fix modprobe tipc failed after switch order of device registration.

I verified the patch v2 works fine, inclue use namespaces together.
I will update syzbot report in patch v3.

Regards,
Junwei