From eaf05be039cf5adfba5b1846452ce89646110fdb Mon Sep 17 00:00:00 2001
From: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Date: Thu, 30 Jun 2005 20:02:18 +0400
Subject: [PATCH] [PATCH] alpha smp fix
As usual, the reason of this breakage is quite silly: in do_entIF, we
are checking for PS == 0 to see whether it was a kernel BUG() or
userspace trap.
It works, unless BUG() happens in interrupt - PS is not 0 in kernel mode
due to non-zero IPL, and the things get messed up horribly then. In
this particular case it was BUG_ON(!irqs_disabled()) triggered in
run_posix_cpu_timers(), so we ended up shooting "current" with the
bursts of one SIGTRAP and three SIGILLs on every timer tick. ;-)
---
arch/alpha/kernel/traps.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index fd7bd17cc960..6f509a644bdd 100644
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c
@@ -240,7 +240,7 @@ do_entIF(unsigned long type, struct pt_regs *regs)
siginfo_t info;
int signo, code;
- if (regs->ps == 0) {
+ if ((regs->ps & ~IPL_MAX) == 0) {
if (type == 1) {
const unsigned int *data
= (const unsigned int *) regs->pc;