Re: [PATCH] fix __mod_timer vs __run_timers deadlock.

Juergen Kreileder
2005-05-03T01:37:10Z

Benjamin Herrenschmidt <benh@kernel.crashing.org> writes:

> On Tue, 2005-05-03 at 00:50 +0200, Juergen Kreileder wrote:
>> Andrew Morton <akpm@osdl.org> writes:
>>
>>> Oleg Nesterov <oleg@tv-sign.ru> wrote:
>>>>
>>>> When __mod_timer() changes timer's base it waits for the
>>>> completion of timer->function. It is just stupid: the caller of
>>>> __mod_timer() can held locks which would prevent completion of
>>>> the timer's handler.
>>>>
>>>> Solution: do not change the base of the currently running timer.
>>>
>>> OK, fingers crossed. Juergen, it would be great if you could test
>>> Oleg's patch sometime.
>>
>> I had one more lockup yesterday but that probably was caused by
>> something else because Azureus is running fine for 24 hours now.
>
> Well, there may be other issues brought by this new timer code
> though. I'm running G5s regulary without a lockup or anything for
> weeks, so it would be interesting if you could try to find out
> what's involved in that other lockup you had.

Sure, if I find a way to reproduce it. It happened only once so far.

BTW, xmon doesn't work for me. 'echo x > /proc/sysrq-trigger' gives
me a :mon> prompt but I can't enter any commands.

Juergen

--
Juergen Kreileder, Blackdown Java-Linux Team