Re: [PATCH v3] blktrace: Fix potentail deadlock between delete & sysfs ops

From: Waiman Long
Date: Fri Aug 18 2017 - 15:55:20 EST


On 08/18/2017 02:07 PM, Bart Van Assche wrote:
> On Fri, 2017-08-18 at 13:54 -0400, Waiman Long wrote:
>> Instead, a global blktrace
>> mutex will be used to serialize the read/write of the blktrace sysfs
>> attributes.
> Hello Waiman,
>
> Using a mutex to serialize code is wrong. What is needed is exact
> documentation of what data structures and/or member variables are
> protected by bdev->bd_mutex and by blktrace_mutex.

Yes, I missed the blk_trace_ioctl(). I should have modified it to use
blktrace_mutex as well.

> Also, please spell "potential" correctly in the subject of this patch.

Will do.

Thanks,
Longman