Andrew Morton wrote:
Keith Owens <[email protected]> wrote:
I had though that too, but it does not allow recovery (i.e. lets reset
>the watchdog and try again).
die_nmi() returns to nmi_watchdog_tick(), nmi_watchdog_tick does the
reset and continues. Patch below.
>Hmm.. just looked at traps.c. Seems die_nmi is NOT called from the nmi
>trap, only from the watchdog. Also, there is a notify in the path to
>the other nmi stuff.
I was looking at unknown_nmi_panic_callback(), which also calls
die_nmi().
traps.c already has several notify_die() calls, nmi.c has none. It is
cleaner to keep all the notification in traps.c, with this small change
to nmi.c to cope with die_nmi() returning.
Index: linux/arch/i386/kernel/nmi.c
===================================================================
--- linux.orig/arch/i386/kernel/nmi.c 2005-07-28 17:22:06.735038510 +1000
+++ linux/arch/i386/kernel/nmi.c 2005-07-29 15:19:00.371196596 +1000
@@ -494,8 +494,10 @@ void nmi_watchdog_tick (struct pt_regs *
* wait a few IRQs (5 seconds) before doing the oops ...
*/
alert_counter[cpu]++;
- if (alert_counter[cpu] == 5*nmi_hz)
+ if (alert_counter[cpu] == 5*nmi_hz) {
die_nmi(regs, "NMI Watchdog detected LOCKUP");
+ alert_counter[cpu] = 0;
+ }
} else {
last_irq_sums[cpu] = sum;
alert_counter[cpu] = 0;
That all makes sense - let's go that way?
Looks good to me. Trimed a bit more fat too. Here is the complete patch.
-
-
George Anzinger [email protected]
HRT (High-res-timers): http://sourceforge.net/projects/high-res-timers/
Source: MontaVista Software, Inc. George Anzinger <[email protected]>
Type: Enhancement
Description:
This patch adds a notify to the die_nmi notify that the system
is about to be taken down. If the notify is handled with a
NOTIFY_STOP return, the system is given a new lease on life.
We also change the nmi watchdog to carry on if die_nmi returns.
This give debug code a chance to a) catch watchdog timeouts and
b) possibly allow the system to continue, realizing that
the time out may be due to debugger activities such as single
stepping which is usually done with "other" cpus held.
Signed-off-by: George Anzinger<[email protected]>
nmi.c | 5 ++++-
traps.c | 4 ++++
2 files changed, 8 insertions(+), 1 deletion(-)
Index: linux-2.6.13-rc/arch/i386/kernel/nmi.c
===================================================================
--- linux-2.6.13-rc.orig/arch/i386/kernel/nmi.c
+++ linux-2.6.13-rc/arch/i386/kernel/nmi.c
@@ -495,8 +495,11 @@ void nmi_watchdog_tick (struct pt_regs *
*/
alert_counter[cpu]++;
if (alert_counter[cpu] == 5*nmi_hz)
+ /*
+ * die_nmi will return ONLY if NOTIFY_STOP happens..
+ */
die_nmi(regs, "NMI Watchdog detected LOCKUP");
- } else {
+
last_irq_sums[cpu] = sum;
alert_counter[cpu] = 0;
}
Index: linux-2.6.13-rc/arch/i386/kernel/traps.c
===================================================================
--- linux-2.6.13-rc.orig/arch/i386/kernel/traps.c
+++ linux-2.6.13-rc/arch/i386/kernel/traps.c
@@ -555,6 +555,10 @@ static DEFINE_SPINLOCK(nmi_print_lock);
void die_nmi (struct pt_regs *regs, const char *msg)
{
+ if (notify_die(DIE_NMIWATCHDOG, "nmi_watchdog", regs,
+ 0, 0, SIGINT) == NOTIFY_STOP)
+ return;
+
spin_lock(&nmi_print_lock);
/*
* We are in trouble anyway, lets at least try
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