From: Paolo Bonzini <pbonzini@redhat.com>
To: He Zhe <zhe.he@windriver.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
"Michael S. Tsirkin" <mst@redhat.com>,
Juri Lelli <jlelli@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: Thu, 15 Jul 2021 13:05:57 +0200 [thread overview]
Message-ID: <c05b358b-1e96-c002-085c-b25e416e7be5@redhat.com> (raw)
In-Reply-To: <e20c3d90-db24-7722-3f89-adadb83a9bf7@windriver.com>
On 15/07/21 12:10, He Zhe wrote:
> The following was provided in this thread. The commit log contains the call traces that I met and fixed back to Apr. 2020.
>
> https://lore.kernel.org/lkml/20210618084412.18257-1-zhe.he@windriver.com/
> 001: WARNING: CPU: 1 PID: 1503 at fs/eventfd.c:73 eventfd_signal+0x85/0xa0
> ---- snip ----
> 001: Call Trace:
> 001: vhost_signal+0x15e/0x1b0 [vhost]
> 001: vhost_add_used_and_signal_n+0x2b/0x40 [vhost]
> 001: handle_rx+0xb9/0x900 [vhost_net]
> 001: handle_rx_net+0x15/0x20 [vhost_net]
> 001: vhost_worker+0xbe/0x120 [vhost]
> 001: kthread+0x106/0x140
> 001: ? log_used.part.0+0x20/0x20 [vhost]
> 001: ? kthread_park+0x90/0x90
> 001: ret_from_fork+0x35/0x40
This call trace is not of a reentrant call; there is only one call to
eventfd_signal. It does fit the symptoms that Daniel reported for
PREEMPT_RT though.
> https://lore.kernel.org/lkml/beac2025-2e11-8ed0-61e2-9f6e633482e8@redhat.com/
This one is about PREEMPT_RT, so it would be fixed by local_lock.
There _may_ be two bugs, so let's start by fixing this one. Once this
one is fixed, we will examine the call stacks of any further reports,
and diagnose whether the second bug (if it exists) is related to vDUSE,
PREEMPT_RT or neeither.
Paolo
next prev parent reply other threads:[~2021-07-15 11:06 UTC|newest]
Thread overview: 45+ 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
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 [this message]
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
2021-07-18 12:42 ` Hillf Danton
2021-07-19 15:38 ` Paolo Bonzini
2021-07-21 7:04 ` Hillf Danton
2021-07-21 7:25 ` Thomas Gleixner
2021-07-21 10:11 ` Hillf Danton
2021-07-21 10:59 ` Paolo Bonzini
2021-07-22 5:58 ` Hillf Danton
2021-07-23 2:23 ` Hillf Danton
2021-07-23 7:59 ` Paolo Bonzini
2021-07-23 9:48 ` Hillf Danton
2021-07-23 10:56 ` Paolo Bonzini
2021-07-24 4:33 ` Hillf Danton
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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