x86, mce: use force_sig_info to kill process in machine check

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>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/arch/x86/kernel/cpu/mcheck/mce_64.c b/arch/x86/kernel/cpu/mcheck/mce_64.c
index 1f184ef..25cf624 100644 (file)
--- a/arch/x86/kernel/cpu/mcheck/mce_64.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_64.c
@@ -295,11 +295,11 @@ void do_machine_check(struct pt_regs * regs, long error_code)
                 * 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);