[PATCH] [8/10] x86: MCE: Use force_sig_info to kill process in machine check

[Andi Kleen <andi@firstfloor.org>]

Impact: bug fix (with tolerant == 3)

do_exit cannot be called directly from the exception handler because 
it can sleep and the exception handler runs on the exception stack.  
Use force_sig() instead.

Based on a earlier patch by Ying Huang who debugged the problem.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
 arch/x86/kernel/cpu/mcheck/mce_64.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux/arch/x86/kernel/cpu/mcheck/mce_64.c
===================================================================
--- linux.orig/arch/x86/kernel/cpu/mcheck/mce_64.c	2009-02-12 11:30:51.000000000 +0100
+++ linux/arch/x86/kernel/cpu/mcheck/mce_64.c	2009-02-12 12:10:20.000000000 +0100
@@ -297,11 +297,11 @@
 		 * If we know that the error was in user space, send a
 		 * SIGBUS.  Otherwise, panic if tolerance is low.
 		 *
-		 * do_exit() takes an awful lot of locks and has a slight
+		 * force_sig() takes an awful lot of locks and has a slight
 		 * risk of deadlocking.
 		 */
 		if (user_space) {
-			do_exit(SIGBUS);
+			force_sig(SIGBUS, current);
 		} else if (panic_on_oops || tolerant < 2) {
 			mce_panic("Uncorrected machine check",
 				&panicm, mcestart);