From: George Anzinger <george@mvista.com>
To: Ingo Molnar <mingo@elte.hu>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: Corey Minyard <cminyard@mvista.com>
Subject: [PATCH] BUG_ON() in ksoftirqd is a bit too agressive...
Date: Wed, 18 May 2005 16:51:29 -0700 [thread overview]
Message-ID: <428BD501.5020905@mvista.com> (raw)
Ksoftirqd is created by init, long after the timer system is up and running. We
have hit the BUG_ON(tasklet_... in this code, i.e. tasklets pending at ksoftirqd
create time. Since, with the RT option to push all softirq code to a thread,
any softirqs are defered to this time, it is easy to hit this bug. Clearly only
a problem for cpu 0. Here is a patch:
Index: linux-2.6.10/kernel/softirq.c
===================================================================
--- linux-2.6.10.orig/kernel/softirq.c
+++ linux-2.6.10/kernel/softirq.c
@@ -514,8 +514,12 @@
switch (action) {
case CPU_UP_PREPARE:
- BUG_ON(per_cpu(tasklet_vec, hotcpu).list);
- BUG_ON(per_cpu(tasklet_hi_vec, hotcpu).list);
+ /* We may have tasklets already scheduled on
+ processor 0, so don't check there. */
+ if (hotcpu != 0) {
+ BUG_ON(per_cpu(tasklet_vec, hotcpu).list);
+ BUG_ON(per_cpu(tasklet_hi_vec, hotcpu).list);
+ }
p = kthread_create(ksoftirqd, hcpu, "ksoftirqd/%d", hotcpu);
if (IS_ERR(p)) {
printk("ksoftirqd for %i failed\n", hotcpu);
--
George Anzinger george@mvista.com
High-res-timers: http://sourceforge.net/projects/high-res-timers/
next reply other threads:[~2005-05-18 23:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-18 23:51 George Anzinger [this message]
2005-05-23 7:28 ` [PATCH] BUG_ON() in ksoftirqd is a bit too agressive Ingo Molnar
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