Messages in this thread Patch in this message | | | Date | Mon, 22 Sep 2008 12:28:34 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH -mm] oprofile: BUG: using smp_processor_id() in preemptible code |
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* Ingo Molnar <mingo@elte.hu> wrote:
> > + local_irq_save(flags); > > __get_cpu_var(switch_index) = 0; > > + local_irq_restore(flags); > > either use __raw_get_cpu_var() if we are for sure not preemptible > here, or fix the preemption status of this codepath.
i've applied the patch below instead to tip/oprofile - agreed?
Ingo
------------> From 45f197ade73ba95681b9803680c75352fc0a1c0a Mon Sep 17 00:00:00 2001 From: Andrea Righi <righi.andrea@gmail.com> Date: Sat, 20 Sep 2008 12:58:40 +0200 Subject: [PATCH] x86, oprofile: BUG: using smp_processor_id() in preemptible code
Add __raw access before setting per cpu variable switch_index, to avoid the following BUG:
[ 449.166827] BUG: using smp_processor_id() in preemptible [00000000] code: modprobe/6998 [ 449.166848] caller is op_nmi_init+0xf0/0x2b0 [oprofile] [ 449.166855] Pid: 6998, comm: modprobe Not tainted 2.6.27-rc5-mm1 #29 [ 449.166860] Call Trace: [ 449.166872] [<ffffffff80362d67>] debug_smp_processor_id+0xd7/0xe0 [ 449.166887] [<ffffffffa00181c0>] op_nmi_init+0xf0/0x2b0 [oprofile] [ 449.166902] [<ffffffffa0018000>] oprofile_init+0x0/0x60 [oprofile] [ 449.166915] [<ffffffffa00180a9>] oprofile_arch_init+0x9/0x30 [oprofile] [ 449.166928] [<ffffffffa001801e>] oprofile_init+0x1e/0x60 [oprofile] [ 449.166937] [<ffffffff8020903b>] _stext+0x3b/0x160 [ 449.166946] [<ffffffff80477985>] __mutex_unlock_slowpath+0xe5/0x190 [ 449.166955] [<ffffffff80262c1a>] trace_hardirqs_on_caller+0xca/0x140 [ 449.166965] [<ffffffff8026f7fc>] sys_init_module+0xdc/0x210 [ 449.166972] [<ffffffff8020b7cb>] system_call_fastpath+0x16/0x1b
Signed-off-by: Andrea Righi <righi.andrea@gmail.com> Acked-by: Robert Richter <robert.richter@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/x86/oprofile/nmi_int.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c index fb4902b..4108d02 100644 --- a/arch/x86/oprofile/nmi_int.c +++ b/arch/x86/oprofile/nmi_int.c @@ -551,7 +551,7 @@ int __init op_nmi_init(struct oprofile_operations *ops) } /* default values, can be overwritten by model */ - __get_cpu_var(switch_index) = 0; + __raw_get_cpu_var(switch_index) = 0; ops->create_files = nmi_create_files; ops->setup = nmi_setup; ops->shutdown = nmi_shutdown;
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