[PATCH][OPROFILE] disable preempt when calling smp_processor_id()

From: Chris Wright
Date: Fri Nov 05 2004 - 19:33:29 EST


Oprofile is hitting many of the below BUG messages.

BUG: using smp_processor_id() in preemptible [00000001] code: sleep/4892
caller is task_exit_notify+0x9/0x17
Call Trace: <ffffffff802ac70f>{smp_processor_id+191}
<ffffffff803ff219>{task_exit_notify+9}
<ffffffff8014a930>{notifier_call_chain+32}
<ffffffff8013d181>{profile_task_exit+49}
<ffffffff8013eb22>{do_exit+34}
<ffffffff80146490>{process_timeout+0}
<ffffffff8013f8c8>{do_group_exit+264}
<ffffffff801106b6>{system_call+126}

smp_processor_id() is called w/out preempt disabled. Use
get_cpu()/put_cpu() instead. Should this be put_cpu_no_resched()?

Signed-off-by: Chris Wright <chrisw@xxxxxxxx>

--- linux-2.6.10-rc1-mm3-smp_processor_id/drivers/oprofile/buffer_sync.c~orig 2004-11-05 15:21:21.551984200 -0800
+++ linux-2.6.10-rc1-mm3-smp_processor_id/drivers/oprofile/buffer_sync.c 2004-11-05 15:23:29.000000000 -0800
@@ -62,7 +62,8 @@
/* To avoid latency problems, we only process the current CPU,
* hoping that most samples for the task are on this CPU
*/
- sync_buffer(smp_processor_id());
+ sync_buffer(get_cpu());
+ put_cpu();
return 0;
}

@@ -86,7 +87,8 @@
/* To avoid latency problems, we only process the current CPU,
* hoping that most samples for the task are on this CPU
*/
- sync_buffer(smp_processor_id());
+ sync_buffer(get_cpu());
+ put_cpu();
return 0;
}

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/