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authorHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>2006-12-08 02:35:58 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-08 08:28:37 -0800
commit6e2ac66470976ad7f57e0948572669b2bdfea2d0 (patch)
parentaad094701c6355cb2b3d74a07ec0496f4a48c787 (diff)
[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>
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 9a352667007..61f5c717a8f 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);