Ingo,
In tracking down the failure of a system running the RT patch we have found a
preemption between the time run_timer_list clears its spinlock and the call back
function (in this case in posix-timers.c) gets its spinlock. The bad news is
that it is possible for the timer to be released at this point leaving the call
back code with a pointer to a bogus timer.
This was/is possible, of course, in SMP systems and is why del_timer_sync()
exists. I suspect that del_timer_sync() needs to also do the "right thing" in
UP RT systems.
This means removing the #ifdef CONFIG_SMP at about line 56 of kernel/timer.c
thus setting up base->running_timer in all cases (or at least in SMP and RT
cases) and also the #ifdef CONFIG_SMP around del_timer_sync() and, of course,
the defines that redirect calls to these functions.
Does this make sense?
--
George Anzinger [email protected]
High-res-timers: http://sourceforge.net/projects/high-res-timers/
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]