Re: [PATCH] nbd: don't warn when reclassifying a busy socket lock

[Hillf Danton <hdanton@sina.com>]

On Tue, 28 Jul 2026 12:53:37 +0800 Hillf Danton wrote:
>On Mon, 20 Jul 2026 10:39:17 +0800 Hillf Danton wrote:
>>On Mon, 20 Jul 2026 10:23:43 +0800 Hillf Danton wrote:
>>>On Sun, Jun 28, 2026 at 10:29 PM Hillf Danton <hdanton@sina.com> wrote:
>>>> For archive purpose, syzbot report [1] where udp was not invovled defies
>>>> what is fixed in d532cddb6c60 ("nbd: Reclassify sockets to avoid lockdep
>>>> circular dependency") -- "Since the UDP socket and the NBD TCP/TLS socket
>>>> are different, this is a false positive."
>>>>
>>>>
>>>> [1] Subject: [syzbot] [net?] possible deadlock in inet_shutdown (3)
>>>> https://lore.kernel.org/lkml/69c37e6a.a70a0220.234938.0045.GAE@google.com/
>>>>
>>>For archive purpose, syzbot report [2] shows deadlock without either udp or
>>>tcp invovled. But it sounds false positive because kernfs node is removed
>>>while the filesystem is filling super block.
>>>
>>>[2] Subject: [syzbot] [kernfs?] possible deadlock in kernfs_remove_by_name_ns (2)
>>>https://lore.kernel.org/lkml/6a5ca0b7.f1649fcc.2a4208.03f3.GAE@google.com/
>>>
>>For archive purpose, syzbot reports [3,4] show deadlock without either udp or
>>tcp invovled.
>>
>>[3] Subject: [syzbot] [kernfs?] possible deadlock in kernfs_iop_permission (2)
>>https://lore.kernel.org/lkml/6a5d14b8.42649fcc.6186.0078.GAE@google.com/
>>
>>[4] Subject: [syzbot] [kernel?] possible deadlock in netif_reset_xps_queues_gt (3)
>>https://lore.kernel.org/lkml/6a5d14b9.42649fcc.6186.0079.GAE@google.com/
>>
>For archive purpose, syzbot report [5] shows deadlock without lock_sock invovled.
>
>[5] Subject: [syzbot] [pm?] possible deadlock in thermal_zone_device_set_mode
>https://lore.kernel.org/lkml/6a676313.073198cf.94f0f.0033.GAE@google.com/
>
For archive purpose, syzbot report [6] shows deadlock without nbd invovled.

[6] Subject: [syzbot] [block?] [cgroups?] possible deadlock in blkcg_deactivate_policy (2)
https://lore.kernel.org/lkml/6a6e8a06.6ce73036.24301b.0015.GAE@google.com/

BTW Eric do you see how difficult it is to fix the fking deadlock?