[PATCH] detect soft lockups
This patch adds a new kernel debug feature: CONFIG_DETECT_SOFTLOCKUP.
When enabled then per-CPU watchdog threads are started, which try to run
once per second. If they get delayed for more than 10 seconds then a
callback from the timer interrupt detects this condition and prints out a
warning message and a stack dump (once per lockup incident). The feature
is otherwise non-intrusive, it doesnt try to unlock the box in any way, it
only gets the debug info out, automatically, and on all CPUs affected by
the lockup.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-Off-By: Matthias Urlichs <smurf@smurf.noris.de>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index 8bbdbda..0178457 100644
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -478,6 +478,11 @@
*/
for (i = 0; i < NR_CPUS; i++)
alert_counter[i] = 0;
+
+ /*
+ * Tickle the softlockup detector too:
+ */
+ touch_softlockup_watchdog();
}
extern void die_nmi(struct pt_regs *, const char *msg);
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
index 6f794a7..b0c5ee2 100644
--- a/arch/i386/kernel/time.c
+++ b/arch/i386/kernel/time.c
@@ -422,6 +422,7 @@
last_timer->resume();
cur_timer = last_timer;
last_timer = NULL;
+ touch_softlockup_watchdog();
return 0;
}
diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index 64a8e05..84cae81 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -463,6 +463,8 @@
*/
for (i = 0; i < NR_CPUS; i++)
per_cpu(nmi_touch, i) = 1;
+
+ touch_softlockup_watchdog();
}
void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason)
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 66bf6dd..2b5d9da 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -1041,6 +1041,7 @@
write_sequnlock_irqrestore(&xtime_lock,flags);
jiffies += sleep_length;
wall_jiffies += sleep_length;
+ touch_softlockup_watchdog();
return 0;
}
