From: Jan Beulich <jbeulich@novell.com>
Date: Fri, 6 Jan 2006 08:11:48 +0000 (-0800)
Subject: [PATCH] i386: don't blindly enable interrupts in die()
X-Git-Tag: v2.6.16-rc1~936^2~210
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e43d674f44dc885a2476cab3537e639d9eaa31a9;p=linux-2.6

[PATCH] i386: don't blindly enable interrupts in die()

Rather than blindly re-enabling interrupts in die(), save their state
upon entry and then restore that state.

If the kernel is in really bad condition and faults with interrupts disabled,
re-enabling them in die() may cause even more trouble, implying more chances
of data corruption.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index ab0e9430f7..bb36a989db 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -306,14 +306,17 @@ void die(const char * str, struct pt_regs * regs, long err)
 		.lock_owner_depth =	0
 	};
 	static int die_counter;
+	unsigned long flags;
 
 	if (die.lock_owner != raw_smp_processor_id()) {
 		console_verbose();
-		spin_lock_irq(&die.lock);
+		spin_lock_irqsave(&die.lock, flags);
 		die.lock_owner = smp_processor_id();
 		die.lock_owner_depth = 0;
 		bust_spinlocks(1);
 	}
+	else
+		local_save_flags(flags);
 
 	if (++die.lock_owner_depth < 3) {
 		int nl = 0;
@@ -340,7 +343,7 @@ void die(const char * str, struct pt_regs * regs, long err)
 
 	bust_spinlocks(0);
 	die.lock_owner = -1;
-	spin_unlock_irq(&die.lock);
+	spin_unlock_irqrestore(&die.lock, flags);
 
 	if (kexec_should_crash(current))
 		crash_kexec(regs);