Re: BUG: rwlock bad magic on CPU, kworker/0:LINE/NUM, ADDR

[Dmitry Vyukov]

On Mon, Nov 30, 2020 at 12:33 PM syzbot
<syzbot+cb987a9c796abc570b47@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    90cf87d1 enetc: Let the hardware auto-advance the taprio b..
> git tree:       net
> console output: https://syzkaller.appspot.com/x/log.txt?x=135479b3500000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=5720c06118e6c4cc
> dashboard link: https://syzkaller.appspot.com/bug?extid=cb987a9c796abc570b47
> compiler:       gcc (GCC) 10.1.0-syz 20200507
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+cb987a9c796abc570b47@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> tipc: 32-bit node address hash set to aa1414ac
> BUG: rwlock bad magic on CPU#0, kworker/0:18/18158, 00000000859f2a8d
> CPU: 0 PID: 18158 Comm: kworker/0:18 Not tainted 5.10.0-rc4-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Workqueue: events tipc_net_finalize_work
> Call Trace:
>  __dump_stack lib/dump_stack.c:77 [inline]
>  dump_stack+0x107/0x163 lib/dump_stack.c:118
>  rwlock_bug kernel/locking/spinlock_debug.c:144 [inline]
>  debug_write_lock_before kernel/locking/spinlock_debug.c:182 [inline]
>  do_raw_write_lock+0x1ef/0x280 kernel/locking/spinlock_debug.c:206
>  tipc_mon_reinit_self+0x1f7/0x630 net/tipc/monitor.c:685

There was also "general protection fault in tipc_mon_reinit_self":
https://syzkaller.appspot.com/bug?id=dc141b9a05cb48d3d9b46837bc2fdc9e7d95dbe9
which also happened once. Smells like an intricate race condition.


>  tipc_net_finalize net/tipc/net.c:134 [inline]
>  tipc_net_finalize+0x1df/0x310 net/tipc/net.c:125
>  process_one_work+0x933/0x15a0 kernel/workqueue.c:2272
>  worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
>  kthread+0x3af/0x4a0 kernel/kthread.c:292
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
>
>
> ---
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