tree e928c8a6b254b288076cd7f552cb7fb361b18d41
parent ccc3c3192ae78dd56dcdf5353fd1a9ef5f9a3e2b
author Andi Kleen <andi@firstfloor.org> 1243454215 +0200
committer H. Peter Anvin <hpa@zytor.com> 1244065512 -0700

x86, mce: implement panic synchronization

In some circumstances multiple CPUs can enter mce_panic() in parallel.
This gives quite confused output because they will all dump the same
machine check buffer.

The other problem is that they would all panic in parallel, but not
process each other's shutdown IPIs because interrupts are disabled.

Detect this situation early on in mce_panic(). On the first CPU
entering will do the panic, the others will just wait to be killed.

For paranoia reasons in case the other CPU dies during the MCE I added
a 5 seconds timeout. If it expires each CPU will panic on its own again.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>