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authorIngo Molnar <mingo@elte.hu>2009-08-03 09:31:54 +0200
committerIngo Molnar <mingo@elte.hu>2009-08-03 09:56:52 +0200
commit47cab6a722d44c71c4f8224017ef548522243cf4 (patch)
tree477bbe67a203d9704792d6ce46a9f1199587ddfe /drivers/char/sysrq.c
parentc1dc0b9c0c8979ce4d411caadff5c0d79dee58bc (diff)
debug lockups: Improve lockup detection, fix generic arch fallback
As Andrew noted, my previous patch ("debug lockups: Improve lockup detection") broke/removed SysRq-L support from architecture that do not provide a __trigger_all_cpu_backtrace implementation. Restore a fallback path and clean up the SysRq-L machinery a bit: - Rename the arch method to arch_trigger_all_cpu_backtrace() - Simplify the define - Document the method a bit - in the hope of more architectures adding support for it. [ The patch touches Sparc code for the rename. ] Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "David S. Miller" <davem@davemloft.net> LKML-Reference: <20090802140809.7ec4bb6b.akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'drivers/char/sysrq.c')
-rw-r--r--drivers/char/sysrq.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index 165f307f30e..50eecfe1d72 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -223,7 +223,20 @@ static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus);
static void sysrq_handle_showallcpus(int key, struct tty_struct *tty)
{
- trigger_all_cpu_backtrace();
+ /*
+ * Fall back to the workqueue based printing if the
+ * backtrace printing did not succeed or the
+ * architecture has no support for it:
+ */
+ if (!trigger_all_cpu_backtrace()) {
+ struct pt_regs *regs = get_irq_regs();
+
+ if (regs) {
+ printk(KERN_INFO "CPU%d:\n", smp_processor_id());
+ show_regs(regs);
+ }
+ schedule_work(&sysrq_showallcpus);
+ }
}
static struct sysrq_key_op sysrq_showallcpus_op = {