Re: [patch 2.6.7] bug_smp_call_function

From: Andrew Morton
Date: Sat Jun 19 2004 - 05:13:19 EST


William Lee Irwin III <wli@xxxxxxxxxxxxxx> wrote:
>
> Keith Owens <kaos@xxxxxxx> wrote:
> >> sg.c has been fixed to no longer call vfree() with interrupts disabled.
> >> Change smp_call_function() from WARN_ON to BUG_ON when interrupts are
> >> disabled. It was only set to WARN_ON because of sg.c.
>
> On Sat, Jun 19, 2004 at 02:44:16AM -0700, Andrew Morton wrote:
> > I prefer the WARN_ON. It is exceedingly unlikely that the bug will cause
> > lockups or memory/data corruption or anything else, so why nuke the user's
> > box when we can trivially continue?
> > We'll be sent the bug report either way.
>
> Calls to smp_call_function() with interrupts off or spinlocks held
> typically causes deadlocks on SMP systems.

No, this doesn't "typically" deadlock. It will deadlock on every ten
millionth call. The preceding 9,999,999 warnings should have imparted
sufficient clue?

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