From: Ed Swierk <eswierk@aristanetworks.com>
Date: Mon, 26 Jan 2009 23:33:31 +0000 (-0800)
Subject: signals, debug: fix BUG: using smp_processor_id() in preemptible code in print_fatal_... 
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=3a9f84d354ce1e19956083c8e691727dea33bd5a;p=linux-2.6-omap-h63xx.git

signals, debug: fix BUG: using smp_processor_id() in preemptible code in print_fatal_signal()

With print-fatal-signals=1 on a kernel with CONFIG_PREEMPT=y, sending an
unexpected signal to a process causes a BUG: using smp_processor_id() in
preemptible code.

get_signal_to_deliver() releases the siglock before calling
print_fatal_signal(), which calls show_regs(), which calls
smp_processor_id(), which is not supposed to be called from a
preemptible thread.

Make sure show_regs() runs with preemption disabled.

Signed-off-by: Ed Swierk <eswierk@aristanetworks.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/kernel/signal.c b/kernel/signal.c
index e73759783dc..b6b36768b75 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -909,7 +909,9 @@ static void print_fatal_signal(struct pt_regs *regs, int signr)
 	}
 #endif
 	printk("\n");
+	preempt_disable();
 	show_regs(regs);
+	preempt_enable();
 }
 
 static int __init setup_print_fatal_signals(char *str)