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| author | Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> | 2006-12-08 02:35:58 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-08 08:28:37 -0800 |
| commit | 6e2ac66470976ad7f57e0948572669b2bdfea2d0 (patch) | |
| tree | aa1e9c2888bae27d96363c5458a871a4c39cbfd2 /kernel/irq | |
| parent | aad094701c6355cb2b3d74a07ec0496f4a48c787 (diff) | |
| download | lwn-6e2ac66470976ad7f57e0948572669b2bdfea2d0.tar.gz lwn-6e2ac66470976ad7f57e0948572669b2bdfea2d0.zip | |
[PATCH] CPEI gets warning at kernel/irq/migration.c:27/move_masked_irq()
While running my MCA test (hardware error injection) on 2.6.19,
I got some warning like following:
> BUG: warning at kernel/irq/migration.c:27/move_masked_irq()
>
> Call Trace:
> [<a000000100013d20>] show_stack+0x40/0xa0
> sp=e00000006b2578d0 bsp=e00000006b2510b0
> [<a000000100013db0>] dump_stack+0x30/0x60
> sp=e00000006b257aa0 bsp=e00000006b251098
> [<a0000001000de430>] move_masked_irq+0xb0/0x240
> sp=e00000006b257aa0 bsp=e00000006b251070
> [<a0000001000de6a0>] move_native_irq+0xe0/0x180
> sp=e00000006b257aa0 bsp=e00000006b251040
> [<a00000010004ff50>] iosapic_end_level_irq+0x30/0xe0
> sp=e00000006b257aa0 bsp=e00000006b251020
> [<a0000001000d94d0>] __do_IRQ+0x170/0x400
> sp=e00000006b257aa0 bsp=e00000006b250fd8
> [<a0000001000116f0>] ia64_handle_irq+0x1b0/0x260
> sp=e00000006b257aa0 bsp=e00000006b250fa8
> [<a00000010000c3a0>] ia64_leave_kernel+0x0/0x280
> sp=e00000006b257aa0 bsp=e00000006b250fa8
> [<a000000100690cf0>] _spin_unlock_irqrestore+0x30/0x60
> sp=e00000006b257c70 bsp=e00000006b250f90
It comes from:
[kernel/irq/migration.c]
26 if (CHECK_IRQ_PER_CPU(desc->status)) {
27 WARN_ON(1);
28 return;
29 }
By putting some printk in kernel, I found that irqbalance is trying to
move CPEI which is handled as PER_CPU irq. That's why.
CPEI(Corrected Platform Error Interrupt) is ia64 specific irq, is
allowed to pin to particular processor which selected by the platform, and
even it is PER_CPU but it has set_affinity handler (=iosapic_set_affinity)
as same as other IO-SAPIC-level interrupts. (I don't know why, but
I guess that there would be typical situation where the handler for
migration is needed, such as hotplug - the processor going to be
offline/hot-removed.)
To shut up this warning, there are 2 way at least:
a) fix CPEI stuff
b) prohibit setting affinity to PER_CPU irq
I'm not sure what stuff of CPEI need to be fixed, but I think that
returning error to attempting move PER_CPU irq is useful for all
applications since it will never work.
Following small patch takes b) style.
It works, the warning disappeared and irqbalance still runs well.
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/irq')
| -rw-r--r-- | kernel/irq/proc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 9a352667007c..61f5c717a8f5 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -54,7 +54,8 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer, unsigned int irq = (int)(long)data, full_count = count, err; cpumask_t new_value, tmp; - if (!irq_desc[irq].chip->set_affinity || no_irq_affinity) + if (!irq_desc[irq].chip->set_affinity || no_irq_affinity || + CHECK_IRQ_PER_CPU(irq_desc[irq].status)) return -EIO; err = cpumask_parse_user(buffer, count, new_value); |