From: Steven Rostedt <rostedt@goodmis.org>
To: Xiao Yang <yangx.jy@cn.fujitsu.com>
Cc: <joel@joelfernandes.org>, <linux-kselftest@vger.kernel.org>,
<linux-trace-devel@vger.kernel.org>,
Xiao Yang <ice_yangxiao@163.com>
Subject: Re: preemptirq_delay_test module can trigger crash on arm64 vm
Date: Fri, 24 Apr 2020 10:01:46 -0400 [thread overview]
Message-ID: <20200424100146.786bcd7f@gandalf.local.home> (raw)
In-Reply-To: <5EA2B0C8.2080706@cn.fujitsu.com>
On Fri, 24 Apr 2020 17:26:32 +0800
Xiao Yang <yangx.jy@cn.fujitsu.com> wrote:
> Hi Steve, Joel
>
> Sorry to bother you.
>
> On my slow arm64 vm, inserting and removing preemptirq_delay_test module
> in loops triggers kernel panic sometimes.
>
> Reproduce steps:
> Do the following steps in loops(more than 10 times):
> [root@CentOS81-aarch64 ]# modprobe preemptirq_delay_test
> test_mode=preempt delay=500000; rmmod preemptirq_delay_test
>
>
Joel,
I never did really look at that module, but doing a quick scan, I see you
never clean up the task you start.
Which means, you can remove the module and the task still exists, and when
it runs, it will execute code that has been freed.
The module exit should still do a kthread_stop() on it. If anything, it
will prevent the task existing after the module is removed.
-- Steve
next prev parent reply other threads:[~2020-04-24 14:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-24 9:26 preemptirq_delay_test module can trigger crash on arm64 vm Xiao Yang
2020-04-24 14:01 ` Steven Rostedt [this message]
2020-04-24 22:19 ` Joel Fernandes
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