* [PATCH] kernel/watchdog.c : fix smp_processor_id() warning
@ 2012-07-25 4:39 Ming Lei
2012-07-26 19:43 ` Don Zickus
0 siblings, 1 reply; 4+ messages in thread
From: Ming Lei @ 2012-07-25 4:39 UTC (permalink / raw)
To: Sameer Nanda, Andrew Morton, Ingo Molnar; +Cc: linux-kernel, Ming Lei
Use raw_smp_processor_id in lockup_detector_bootcpu_resume()
because it is enough when non-boot CPUs are offline.
This patch fixes the following warning when DEBUG_PREEMPT
is enabled.
[ 168.259429] BUG: using smp_processor_id() in preemptible [00000000] code: pm/1577
[ 168.259460] caller is lockup_detector_bootcpu_resume+0x8/0x48
[ 168.259490] [<c001558c>] (unwind_backtrace+0x0/0x11c) from [<c0296874>] (debug_smp_processor_id+0xbc/0xf0)
[ 168.259521] [<c0296874>] (debug_smp_processor_id+0xbc/0xf0) from [<c0090114>] (lockup_detector_bootcpu_res
ume+0x8/0x48)
[ 168.259552] [<c0090114>] (lockup_detector_bootcpu_resume+0x8/0x48) from [<c006facc>] (suspend_devices_and_
enter+0x1f8/0x358)
[ 168.259552] [<c006facc>] (suspend_devices_and_enter+0x1f8/0x358) from [<c006fd68>] (pm_suspend+0x13c/0x204
)
[ 168.259582] [<c006fd68>] (pm_suspend+0x13c/0x204) from [<c006f0d0>] (state_store+0xb0/0xd4)
[ 168.259582] [<c006f0d0>] (state_store+0xb0/0xd4) from [<c028a3d8>] (kobj_attr_store+0x14/0x20)
[ 168.259613] [<c028a3d8>] (kobj_attr_store+0x14/0x20) from [<c014d344>] (sysfs_write_file+0x10c/0x140)
[ 168.259643] [<c014d344>] (sysfs_write_file+0x10c/0x140) from [<c00f5a88>] (vfs_write+0xb0/0x138)
[ 168.259643] [<c00f5a88>] (vfs_write+0xb0/0x138) from [<c00f5ce8>] (sys_write+0x3c/0x68)
[ 168.259674] [<c00f5ce8>] (sys_write+0x3c/0x68) from [<c000e020>] (ret_fast_syscall+0x0/0x48)
[ 168.260375] Enabling non-boot CPUs ...
Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
kernel/watchdog.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 69add8a..7ddb11b 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -623,7 +623,7 @@ static struct notifier_block cpu_nfb = {
*/
void lockup_detector_bootcpu_resume(void)
{
- void *cpu = (void *)(long)smp_processor_id();
+ void *cpu = (void *)(long)raw_smp_processor_id();
cpu_callback(&cpu_nfb, CPU_DEAD_FROZEN, cpu);
cpu_callback(&cpu_nfb, CPU_UP_PREPARE_FROZEN, cpu);
--
1.7.9.5
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] kernel/watchdog.c : fix smp_processor_id() warning
2012-07-25 4:39 [PATCH] kernel/watchdog.c : fix smp_processor_id() warning Ming Lei
@ 2012-07-26 19:43 ` Don Zickus
2012-07-27 0:38 ` Ming Lei
0 siblings, 1 reply; 4+ messages in thread
From: Don Zickus @ 2012-07-26 19:43 UTC (permalink / raw)
To: Ming Lei; +Cc: Sameer Nanda, Andrew Morton, Ingo Molnar, linux-kernel
On Wed, Jul 25, 2012 at 12:39:45PM +0800, Ming Lei wrote:
> Use raw_smp_processor_id in lockup_detector_bootcpu_resume()
> because it is enough when non-boot CPUs are offline.
>
> This patch fixes the following warning when DEBUG_PREEMPT
> is enabled.
Is this patched on top of linux-next?
It seems right based on the code usage. Though it makes me sad the resume
code has to hack into the cpu notifiers like that.
Cheers,
Don
>
> [ 168.259429] BUG: using smp_processor_id() in preemptible [00000000] code: pm/1577
> [ 168.259460] caller is lockup_detector_bootcpu_resume+0x8/0x48
> [ 168.259490] [<c001558c>] (unwind_backtrace+0x0/0x11c) from [<c0296874>] (debug_smp_processor_id+0xbc/0xf0)
> [ 168.259521] [<c0296874>] (debug_smp_processor_id+0xbc/0xf0) from [<c0090114>] (lockup_detector_bootcpu_res
> ume+0x8/0x48)
> [ 168.259552] [<c0090114>] (lockup_detector_bootcpu_resume+0x8/0x48) from [<c006facc>] (suspend_devices_and_
> enter+0x1f8/0x358)
> [ 168.259552] [<c006facc>] (suspend_devices_and_enter+0x1f8/0x358) from [<c006fd68>] (pm_suspend+0x13c/0x204
> )
> [ 168.259582] [<c006fd68>] (pm_suspend+0x13c/0x204) from [<c006f0d0>] (state_store+0xb0/0xd4)
> [ 168.259582] [<c006f0d0>] (state_store+0xb0/0xd4) from [<c028a3d8>] (kobj_attr_store+0x14/0x20)
> [ 168.259613] [<c028a3d8>] (kobj_attr_store+0x14/0x20) from [<c014d344>] (sysfs_write_file+0x10c/0x140)
> [ 168.259643] [<c014d344>] (sysfs_write_file+0x10c/0x140) from [<c00f5a88>] (vfs_write+0xb0/0x138)
> [ 168.259643] [<c00f5a88>] (vfs_write+0xb0/0x138) from [<c00f5ce8>] (sys_write+0x3c/0x68)
> [ 168.259674] [<c00f5ce8>] (sys_write+0x3c/0x68) from [<c000e020>] (ret_fast_syscall+0x0/0x48)
> [ 168.260375] Enabling non-boot CPUs ...
>
> Signed-off-by: Ming Lei <ming.lei@canonical.com>
> ---
> kernel/watchdog.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index 69add8a..7ddb11b 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -623,7 +623,7 @@ static struct notifier_block cpu_nfb = {
> */
> void lockup_detector_bootcpu_resume(void)
> {
> - void *cpu = (void *)(long)smp_processor_id();
> + void *cpu = (void *)(long)raw_smp_processor_id();
>
> cpu_callback(&cpu_nfb, CPU_DEAD_FROZEN, cpu);
> cpu_callback(&cpu_nfb, CPU_UP_PREPARE_FROZEN, cpu);
> --
> 1.7.9.5
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] kernel/watchdog.c : fix smp_processor_id() warning
2012-07-26 19:43 ` Don Zickus
@ 2012-07-27 0:38 ` Ming Lei
2012-07-27 14:37 ` Don Zickus
0 siblings, 1 reply; 4+ messages in thread
From: Ming Lei @ 2012-07-27 0:38 UTC (permalink / raw)
To: Don Zickus; +Cc: Sameer Nanda, Andrew Morton, Ingo Molnar, linux-kernel
On Fri, Jul 27, 2012 at 3:43 AM, Don Zickus <dzickus@redhat.com> wrote:
> On Wed, Jul 25, 2012 at 12:39:45PM +0800, Ming Lei wrote:
>> Use raw_smp_processor_id in lockup_detector_bootcpu_resume()
>> because it is enough when non-boot CPUs are offline.
>>
>> This patch fixes the following warning when DEBUG_PREEMPT
>> is enabled.
>
> Is this patched on top of linux-next?
Yes.
The warning is introduced by the commit below:
7fb860ff90ae970cf62cf676dfc1addcf8415674
(NMI watchdog: fix for lockup detector breakage on resume)
> It seems right based on the code usage. Though it makes me sad the resume
> code has to hack into the cpu notifiers like that.
Thanks,
--
Ming Lei
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] kernel/watchdog.c : fix smp_processor_id() warning
2012-07-27 0:38 ` Ming Lei
@ 2012-07-27 14:37 ` Don Zickus
0 siblings, 0 replies; 4+ messages in thread
From: Don Zickus @ 2012-07-27 14:37 UTC (permalink / raw)
To: Ming Lei; +Cc: Sameer Nanda, Andrew Morton, Ingo Molnar, linux-kernel
On Fri, Jul 27, 2012 at 08:38:21AM +0800, Ming Lei wrote:
> On Fri, Jul 27, 2012 at 3:43 AM, Don Zickus <dzickus@redhat.com> wrote:
> > On Wed, Jul 25, 2012 at 12:39:45PM +0800, Ming Lei wrote:
> >> Use raw_smp_processor_id in lockup_detector_bootcpu_resume()
> >> because it is enough when non-boot CPUs are offline.
> >>
> >> This patch fixes the following warning when DEBUG_PREEMPT
> >> is enabled.
> >
> > Is this patched on top of linux-next?
>
> Yes.
>
> The warning is introduced by the commit below:
>
> 7fb860ff90ae970cf62cf676dfc1addcf8415674
> (NMI watchdog: fix for lockup detector breakage on resume)
Ok, so I can respin this to give my SoB, if Andrew wants. But at the same
time this patch will become obsolete (or broken) with tglx's hotplug
infrastructure changes.
Not sure what to do here.
Andrew?
Cheers,
Don
^ permalink raw reply [flat|nested] 4+ messages in thread
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2012-07-25 4:39 [PATCH] kernel/watchdog.c : fix smp_processor_id() warning Ming Lei
2012-07-26 19:43 ` Don Zickus
2012-07-27 0:38 ` Ming Lei
2012-07-27 14:37 ` Don Zickus
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