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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-08-21 09:23:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-08-21 09:23:57 -0700 |
| commit | 83d349f35e1ae72268c5104dbf9ab2ae635425d4 (patch) | |
| tree | 329927ef85bd5b508434421cd275bdf67a4cca98 | |
| parent | 429966b8f644dda2afddb4f834a944e9b46a7645 (diff) | |
| download | linux-83d349f35e1ae72268c5104dbf9ab2ae635425d4.tar.bz2 | |
x86: don't send an IPI to the empty set of CPU's
The default_send_IPI_mask_logical() function uses the "flat" APIC mode
to send an IPI to a set of CPU's at once, but if that set happens to be
empty, some older local APIC's will apparently be rather unhappy. So
just warn if a caller gives us an empty mask, and ignore it.
This fixes a regression in 2.6.30.x, due to commit 4595f9620 ("x86:
change flush_tlb_others to take a const struct cpumask"), documented
here:
http://bugzilla.kernel.org/show_bug.cgi?id=13933
which causes a silent lock-up. It only seems to happen on PPro, P2, P3
and Athlon XP cores. Most developers sadly (or not so sadly, if you're
a developer..) have more modern CPU's. Also, on x86-64 we don't use the
flat APIC mode, so it would never trigger there even if the APIC didn't
like sending an empty IPI mask.
Reported-by: Pavel Vilim <wylda@volny.cz>
Reported-and-tested-by: Thomas Björnell <thomas.bjornell@gmail.com>
Reported-and-tested-by: Martin Rogge <marogge@onlinehome.de>
Cc: Mike Travis <travis@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/x86/kernel/apic/ipi.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/ipi.c b/arch/x86/kernel/apic/ipi.c index dbf5445727a9..6ef00ba4c886 100644 --- a/arch/x86/kernel/apic/ipi.c +++ b/arch/x86/kernel/apic/ipi.c @@ -106,6 +106,9 @@ void default_send_IPI_mask_logical(const struct cpumask *cpumask, int vector) unsigned long mask = cpumask_bits(cpumask)[0]; unsigned long flags; + if (WARN_ONCE(!mask, "empty IPI mask")) + return; + local_irq_save(flags); WARN_ON(mask & ~cpumask_bits(cpu_online_mask)[0]); __default_send_IPI_dest_field(mask, vector, apic->dest_logical); |