From: Paolo Bonzini <pbonzini@redhat.com>
To: Daniel Bristot de Oliveira <bristot@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
"Jason Wang (jasowang@redhat.com)" <jasowang@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: 5.13-rt1 + KVM = WARNING: at fs/eventfd.c:74 eventfd_signal()
Date: Wed, 14 Jul 2021 10:10:08 +0200 [thread overview]
Message-ID: <8dfc0ee9-b97a-8ca8-d057-31c8cad3f5b6@redhat.com> (raw)
In-Reply-To: <df278db6-1fc0-3d42-9c0e-f5a085c6351e@redhat.com>
On 14/07/21 10:01, Daniel Bristot de Oliveira wrote:
> Hey
>
> I use kvm-vm for regular development, and while using the kernel-rt v5.13-rt1
> (the latest) on the host, and a regular kernel on the guest, after a while,
> this happens:
>
> [ 1723.404979] ------------[ cut here ]------------
> [ 1723.404981] WARNING: CPU: 12 PID: 2554 at fs/eventfd.c:74 eventfd_signal+0x7e/0x90
> [ 1723.405055] RIP: 0010:eventfd_signal+0x7e/0x90
> [ 1723.405059] Code: 01 00 00 00 be 03 00 00 00 4c 89 ef e8 5b ec d9 ff 65 ff 0d e4 34 c9 5a 4c 89 ef e8 ec a8 86 00 4c 89 e0 5b 5d 41 5c 41 5d c3 <0f> 0b 45 31 e4 5b 5d 4c 89 e0 41 5c 41 5d c3 0f 1f 00 0f 1f 44 00
> [ 1723.405078] vhost_tx_batch.constprop.0+0x7d/0xc0 [vhost_net]
> [ 1723.405083] handle_tx_copy+0x15b/0x5c0 [vhost_net]
> [ 1723.405088] ? __vhost_add_used_n+0x200/0x200 [vhost]
> [ 1723.405092] handle_tx+0xa5/0xe0 [vhost_net]
> [ 1723.405095] vhost_worker+0x93/0xd0 [vhost]
> [ 1723.405099] kthread+0x186/0x1a0
> [ 1723.405103] ? __kthread_parkme+0xa0/0xa0
> [ 1723.405105] ret_from_fork+0x22/0x30
> [ 1723.405110] ---[ end trace 0000000000000002 ]---
The WARN has this comment above:
/*
* Deadlock or stack overflow issues can happen if we recurse here
* through waitqueue wakeup handlers. If the caller users potentially
* nested waitqueues with custom wakeup handlers, then it should
* check eventfd_signal_count() before calling this function. If
* it returns true, the eventfd_signal() call should be deferred to a
* safe context.
*/
This was added in 2020, so it's unlikely to be the direct cause of the
change. What is a known-good version for the host?
Since it is not KVM stuff, I'm CCing Michael and Jason.
Paolo
next prev parent reply other threads:[~2021-07-14 8:10 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-14 8:01 5.13-rt1 + KVM = WARNING: at fs/eventfd.c:74 eventfd_signal() Daniel Bristot de Oliveira
2021-07-14 8:10 ` Paolo Bonzini [this message]
2021-07-14 9:23 ` Jason Wang
2021-07-14 10:35 ` Paolo Bonzini
2021-07-14 10:41 ` Michael S. Tsirkin
2021-07-14 10:44 ` Paolo Bonzini
2021-07-14 12:20 ` Daniel Bristot de Oliveira
2021-07-15 4:14 ` Jason Wang
2021-07-15 5:58 ` Paolo Bonzini
2021-07-15 6:45 ` Jason Wang
2021-07-15 8:22 ` Daniel Bristot de Oliveira
2021-07-15 8:44 ` He Zhe
2021-07-15 9:51 ` Paolo Bonzini
2021-07-15 10:10 ` He Zhe
2021-07-15 11:05 ` Paolo Bonzini
2021-07-16 2:26 ` Jason Wang
2021-07-16 2:43 ` He Zhe
2021-07-16 2:46 ` Jason Wang
2021-07-15 9:46 ` Paolo Bonzini
2021-07-15 12:34 ` Daniel Bristot de Oliveira
[not found] ` <20210715102249.2205-1-hdanton@sina.com>
2021-07-15 12:31 ` Daniel Bristot de Oliveira
[not found] ` <20210716020611.2288-1-hdanton@sina.com>
2021-07-16 6:54 ` Paolo Bonzini
[not found] ` <20210716075539.2376-1-hdanton@sina.com>
2021-07-16 7:59 ` Paolo Bonzini
[not found] ` <20210716093725.2438-1-hdanton@sina.com>
2021-07-16 11:55 ` Paolo Bonzini
[not found] ` <20210718124219.1521-1-hdanton@sina.com>
2021-07-19 15:38 ` Paolo Bonzini
[not found] ` <20210721070452.1008-1-hdanton@sina.com>
2021-07-21 7:25 ` Thomas Gleixner
[not found] ` <20210721101119.1103-1-hdanton@sina.com>
2021-07-21 10:59 ` Paolo Bonzini
[not found] ` <20210723022356.1301-1-hdanton@sina.com>
2021-07-23 7:59 ` Paolo Bonzini
[not found] ` <20210723094830.1375-1-hdanton@sina.com>
2021-07-23 10:56 ` Paolo Bonzini
[not found] ` <20210724043320.1654-1-hdanton@sina.com>
2021-07-26 11:03 ` Paolo Bonzini
2021-07-28 8:06 ` Thomas Gleixner
2021-07-28 10:21 ` Paolo Bonzini
2021-07-28 19:07 ` Thomas Gleixner
2021-07-29 11:01 ` [PATCH] eventfd: Make signal recursion protection a task bit Thomas Gleixner
2021-07-29 14:32 ` Daniel Bristot de Oliveira
2021-07-29 19:23 ` Daniel Bristot de Oliveira
2021-08-26 7:03 ` Jason Wang
2021-08-27 23:41 ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
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