[PATCH] x86_64: Don't run NMI watchdog during machine checks

Machine checks can stall the machine for a long time and
it's not good to trigger the nmi watchdog during that.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/arch/x86_64/kernel/mce.c b/arch/x86_64/kernel/mce.c
index 10b3e348fc99..6f0790e8b6d3 100644
--- a/arch/x86_64/kernel/mce.c
+++ b/arch/x86_64/kernel/mce.c
@@ -29,6 +29,8 @@
 #define MISC_MCELOG_MINOR 227
 #define NR_BANKS 6
 
+atomic_t mce_entry;
+
 static int mce_dont_init;
 
 /* 0: always panic, 1: panic if deadlock possible, 2: try to avoid panic,
@@ -172,10 +174,12 @@ void do_machine_check(struct pt_regs * regs, long error_code)
         int i;
         int panicm_found = 0;
 
+        atomic_inc(&mce_entry);
+
         if (regs)
                 notify_die(DIE_NMI, "machine check", regs, error_code, 18, SIGKILL);
         if (!banks)
-                return;
+                goto out2;
 
         memset(&m, 0, sizeof(struct mce));
         m.cpu = safe_smp_processor_id();
@@ -266,6 +270,8 @@ void do_machine_check(struct pt_regs * regs, long error_code)
  out:
         /* Last thing done in the machine check exception to clear state. */
         wrmsrl(MSR_IA32_MCG_STATUS, 0);
+ out2:
+        atomic_dec(&mce_entry);
 }
 
 /*