Re: [RFC][PATCH] timers fixes/improvements

From: Andrew Morton
Date: Mon May 09 2005 - 16:43:39 EST


Christoph Lameter <christoph@xxxxxxxxxxx> wrote:
>
> We have some strange race conditions as a result of the timer
> scalability fixes.
>
> ptype_all is set to 0x10:0x10 on faster systems (Xeon 3.6Ghz).
> Slower systems do fine(Xeon 3.0Ghz) and do not corrupt ptype_all.
>
> Its not clear to me how ptype_all could relate to timer operations

I'd do `nm -n vmlinux', see which data structures the linker placed nearby
to ptype_all and then go looking for overruns against them.

ptype_base is an array, but I cannot see any race around ptype_base. So
look to see if ptype_base is corrupted as well, keep walking back through
memory, see where the scribble starts.

> but
> if I apply these timer patches I get ptype_all corruption.
>
> timers-fixes-improvements.patch
> timers-fixes-improvements-smp_processor_id-fix.patch
> timers-fixes-improvements-fix.patch
> timer-deadlock-fix
> (It does not matter if the last three are applied)

2.6.12-rc3-mm3 has different patches:

timers-fixes-improvements.patch
timers-fixes-improvements-smp_processor_id-fix.patch
timers-fixes-improvements-fix.patch
timers-fix-__mod_timer-vs-__run_timers-deadlock.patch
timers-fix-__mod_timer-vs-__run_timers-deadlock-tidy.patch
timers-comments-update.patch
kernel-timerc-remove-a-goto-construct.patch

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