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Subject: Re: [PATCH] sample-trace-array: Fix sleeping function called from
 invalid context
To:     Steven Rostedt <rostedt@goodmis.org>,
        Kefeng Wang <wangkefeng.wang@huawei.com>
Cc:     linux-kernel@vger.kernel.org,
        Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
References: <20200608075437.1760242-1-wangkefeng.wang@huawei.com>
 <20200608103709.39afa15f@gandalf.local.home>
From:   Divya Indi <divya.indi@oracle.com>
Message-ID: <3a672473-8621-ff7e-42d5-b4d9412267e8@oracle.com>
Date:   Mon, 8 Jun 2020 17:10:42 -0700
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Hi Steve,

Sure, I am looking into it and reviewing the patch.

Thanks,
Divya

On 6/8/20 7:37 AM, Steven Rostedt wrote:
> On Mon, 8 Jun 2020 07:54:37 +0000
> Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
>
>>  BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
>>  in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/5
>>  1 lock held by swapper/5/0:
>>   #0: ffff80001002bd90 (samples/ftrace/sample-trace-array.c:38){+.-.}-{0:0}, at: call_timer_fn+0x8/0x3e0
>>  CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.7.0+ #8
>>  Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
>>  Call trace:
>>   dump_backtrace+0x0/0x1a0
>>   show_stack+0x20/0x30
>>   dump_stack+0xe4/0x150
>>   ___might_sleep+0x160/0x200
>>   __might_sleep+0x58/0x90
>>   __mutex_lock+0x64/0x948
>>   mutex_lock_nested+0x3c/0x58
>>   __ftrace_set_clr_event+0x44/0x88
>>   trace_array_set_clr_event+0x24/0x38
>>   mytimer_handler+0x34/0x40 [sample_trace_array]
>>
>> mutex_lock() will be called in interrupt context, using workqueueu to fix it.
>>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
>>
> Divya,
>
> Can you give a Reviewed-by for this?
>
> -- Steve