From: Satyam Sharma <satyam@infradead.org>
Date: Wed, 24 Oct 2007 16:23:50 +0000 (+0200)
Subject: sched: use show_regs() to improve __schedule_bug() output
X-Git-Tag: v2.6.24-rc2~145^2~7
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=838225b48edc971620cbeb292034dabd2b0d7d1d;p=linux-2.6-omap-h63xx.git

sched: use show_regs() to improve __schedule_bug() output

A full register dump along with stack backtrace would make the
"scheduling while atomic" message more helpful. Use show_regs() instead
of dump_stack() for this. We already know we're atomic in here (that is
why this function was called) so show_regs()'s atomicity expectations
are guaranteed.

Also, modify the output of the "BUG: scheduling while atomic:" header a
bit to keep task->comm and task->pid together and preempt_count() after
them.

Signed-off-by: Satyam Sharma <satyam@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/kernel/sched.c b/kernel/sched.c
index af02a4de069..d1e6663d3ab 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -66,6 +66,7 @@
 #include <linux/pagemap.h>
 
 #include <asm/tlb.h>
+#include <asm/irq_regs.h>
 
 /*
  * Scheduler clock - returns current time in nanosec units.
@@ -3507,12 +3508,19 @@ EXPORT_SYMBOL(sub_preempt_count);
  */
 static noinline void __schedule_bug(struct task_struct *prev)
 {
-	printk(KERN_ERR "BUG: scheduling while atomic: %s/0x%08x/%d\n",
-		prev->comm, preempt_count(), task_pid_nr(prev));
+	struct pt_regs *regs = get_irq_regs();
+
+	printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
+		prev->comm, prev->pid, preempt_count());
+
 	debug_show_held_locks(prev);
 	if (irqs_disabled())
 		print_irqtrace_events(prev);
-	dump_stack();
+
+	if (regs)
+		show_regs(regs);
+	else
+		dump_stack();
 }
 
 /*