lkml.org 
[lkml]   [2013]   [Mar]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH] thinkpad-acpi: fix potential suspend blocking issue
From
On Tue, Mar 5, 2013 at 10:05 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> On 03/05, Mandeep Singh Baines wrote:
>>
>> On Tue, Mar 5, 2013 at 9:48 AM, Oleg Nesterov <oleg@redhat.com> wrote:
>> > On 03/05, Mandeep Singh Baines wrote:
>> >>
>> >> @@ -2462,13 +2462,13 @@ static int hotkey_kthread(void *data)
>> >> unsigned int poll_freq;
>> >> bool was_frozen;
>> >>
>> >> + set_freezable();
>> >> +
>> >> mutex_lock(&hotkey_thread_mutex);
>> >>
>> >> if (tpacpi_lifecycle == TPACPI_LIFE_EXITING)
>> >> goto exit;
>> >>
>> >> - set_freezable();
>> >> -
>> >
>> > I don't understand this code... but don't we have the same problem
>> > with kthread_freezable_should_stop() below? It can call __refrigerator()
>> > too under the same lock.
>> >
>>
>> I don't think the lock is held at that point. There is an unlock right
>> before entering the while loop and at the bottom of the loop.
>
> Hmm... Afaics this is another lock, hotkey_thread_data_mutex. But
> hotkey_thread_mutex is still held.
>

Ah. You're right. The two names were similar so that confused me. I'm
also looking at this code for the first time:)

This mutex seems wrong. Its held the entire time the kthread is
running. I think its used to synchronize on the exit of the kthread. A
completion would more appropriate in that case.

Regards,
Mandeep

> Oleg.
>


\
 
 \ /
  Last update: 2013-03-05 22:42    [W:0.068 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site