From: He Zhe <zhe.he@windriver.com>
To: Paolo Bonzini <pbonzini@redhat.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 18:10:47 +0800 [thread overview]
Message-ID: <e20c3d90-db24-7722-3f89-adadb83a9bf7@windriver.com> (raw)
In-Reply-To: <b73f8986-9071-6fbb-5c6a-d7892ba2302b@redhat.com>
On 7/15/21 5:51 PM, Paolo Bonzini wrote:
> On 15/07/21 10:44, He Zhe wrote:
>> It was to increase the recursion depth to 2 so that vhost_worker and
>> kvm_vcpu_ioctl syscall could work in parallel
>
> The count is per-CPU, so parallel operations cannot cause it to become 2. Your patch might fix calls from ioeventfd to vhost_worker to another eventfd, but not *parallel* operation of KVM and vhost (except on PREEMPT_RT).
>
> You should identify the exact callstack that caused the warning for vDUSE, and document that one in the commit message, so that reviewers can understand the issue.
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/
And the problem has been reported many times until last month. So when this patch was pointed at in this thread, I thought it was still the same case.
https://lore.kernel.org/lkml/beac2025-2e11-8ed0-61e2-9f6e633482e8@redhat.com/
https://lore.kernel.org/lkml/20210703043039-mutt-send-email-mst@kernel.org/
Zhe
>
> Paolo
>
next prev parent reply other threads:[~2021-07-15 10:11 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 [this message]
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
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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