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Groups > linux.kernel > #1489272 > unrolled thread
| Started by | Nicolai Stange <nicstange@gmail.com> |
|---|---|
| First post | 2016-09-22 20:20 +0200 |
| Last post | 2016-09-23 09:30 +0200 |
| Articles | 4 — 2 participants |
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[PATCH] smp: smp_call_on_cpu(): use INIT_WORK_ONSTACK() for automatic work_struct Nicolai Stange <nicstange@gmail.com> - 2016-09-22 20:20 +0200
Re: [PATCH] smp: smp_call_on_cpu(): use INIT_WORK_ONSTACK() for automatic work_struct Peter Zijlstra <peterz@infradead.org> - 2016-09-22 20:50 +0200
Re: [PATCH] smp: smp_call_on_cpu(): use INIT_WORK_ONSTACK() for automatic work_struct Nicolai Stange <nicstange@gmail.com> - 2016-09-22 21:20 +0200
Re: [PATCH] smp: smp_call_on_cpu(): use INIT_WORK_ONSTACK() for automatic work_struct Peter Zijlstra <peterz@infradead.org> - 2016-09-23 09:30 +0200
| From | Nicolai Stange <nicstange@gmail.com> |
|---|---|
| Date | 2016-09-22 20:20 +0200 |
| Subject | [PATCH] smp: smp_call_on_cpu(): use INIT_WORK_ONSTACK() for automatic work_struct |
| Message-ID | <skgLf-1mw-21@gated-at.bofh.it> |
This new warning
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 0 PID: 82 Comm: kworker/0:1 Not tainted 4.8.0-rc6+ #360
Hardware name: Dell Inc. Latitude E6540/0725FP, BIOS A10 06/26/2014
Workqueue: events smp_call_on_cpu_callback
[...]
Call Trace:
[<ffffffff9542fa55>] dump_stack+0x68/0x93
[<ffffffff950ede3a>] register_lock_class+0x54a/0x550
[<ffffffff950f0178>] __lock_acquire+0x88/0x12a0
[<ffffffff95106f0d>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[<ffffffff950f17b9>] lock_acquire+0xe9/0x1d0
[<ffffffff950b2fe7>] ? process_one_work+0x197/0x6c0
[<ffffffff950b3040>] process_one_work+0x1f0/0x6c0
[<ffffffff950b2fe7>] ? process_one_work+0x197/0x6c0
[<ffffffff950b355e>] worker_thread+0x4e/0x4a0
[<ffffffff950b3510>] ? process_one_work+0x6c0/0x6c0
[<ffffffff950b3510>] ? process_one_work+0x6c0/0x6c0
[<ffffffff950baf0f>] kthread+0xff/0x120
[<ffffffff950bae10>] ? kthread_park+0x60/0x60
[<ffffffff9584d217>] ret_from_fork+0x27/0x40
dcdbas dcdbas: Dell Systems Management Base Driver (version 5.6.0-3.2)
can be bisected to commit e23f22b5cb9e ("dcdbas: Make use of
smp_call_on_cpu()").
The reason is that smp_call_on_cpu(), introduced with commit df8ce9d78a4e
("smp: Add function to execute a function synchronously on a CPU"),
initializes a work_struct with automatic storage duration by means of
__WORK_INITIALIZER().
Use INIT_WORK_ONSTACK() there instead, just like the very similar
work_on_cpu() does.
Fixes: df8ce9d78a4e ("smp: Add function to execute a function
synchronously on a CPU")
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
---
kernel/smp.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/smp.c b/kernel/smp.c
index f4f6137..a129ac3 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -759,7 +759,6 @@ static void smp_call_on_cpu_callback(struct work_struct *work)
int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
{
struct smp_call_on_cpu_struct sscs = {
- .work = __WORK_INITIALIZER(sscs.work, smp_call_on_cpu_callback),
.done = COMPLETION_INITIALIZER_ONSTACK(sscs.done),
.func = func,
.data = par,
@@ -769,9 +768,13 @@ int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
if (cpu >= nr_cpu_ids || !cpu_online(cpu))
return -ENXIO;
+ INIT_WORK_ONSTACK(&sscs.work, smp_call_on_cpu_callback);
+
queue_work_on(cpu, system_wq, &sscs.work);
wait_for_completion(&sscs.done);
+ destroy_work_on_stack(&sscs.work);
+
return sscs.ret;
}
EXPORT_SYMBOL_GPL(smp_call_on_cpu);
--
2.10.0
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| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Date | 2016-09-22 20:50 +0200 |
| Subject | Re: [PATCH] smp: smp_call_on_cpu(): use INIT_WORK_ONSTACK() for automatic work_struct |
| Message-ID | <skheh-1xN-9@gated-at.bofh.it> |
| In reply to | #1489272 |
On Thu, Sep 22, 2016 at 08:17:58PM +0200, Nicolai Stange wrote: > This new warning > > INFO: trying to register non-static key. > the code is fine but needs lockdep annotation. > turning off the locking correctness validator. > CPU: 0 PID: 82 Comm: kworker/0:1 Not tainted 4.8.0-rc6+ #360 > Hardware name: Dell Inc. Latitude E6540/0725FP, BIOS A10 06/26/2014 > Workqueue: events smp_call_on_cpu_callback https://lkml.kernel.org/r/tip-8db549491c4a3ce9e1d509b75f78516e497f48ec@git.kernel.org
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| From | Nicolai Stange <nicstange@gmail.com> |
|---|---|
| Date | 2016-09-22 21:20 +0200 |
| Message-ID | <skhHk-1Xw-13@gated-at.bofh.it> |
| In reply to | #1489361 |
Peter Zijlstra <peterz@infradead.org> writes: > On Thu, Sep 22, 2016 at 08:17:58PM +0200, Nicolai Stange wrote: >> This new warning >> >> INFO: trying to register non-static key. >> the code is fine but needs lockdep annotation. >> turning off the locking correctness validator. >> CPU: 0 PID: 82 Comm: kworker/0:1 Not tainted 4.8.0-rc6+ #360 >> Hardware name: Dell Inc. Latitude E6540/0725FP, BIOS A10 06/26/2014 >> Workqueue: events smp_call_on_cpu_callback > > https://lkml.kernel.org/r/tip-8db549491c4a3ce9e1d509b75f78516e497f48ec@git.kernel.org Ah, thanks for letting me know. One minor question regarding your patch though: it hasn't got a destroy_work_on_stack(). Isn't one needed because of INIT_WORK_ONSTACK() -> __INIT_WORK() -> __init_work() -> debug_object_init_on_stack() ? At least work_on_cpu() destroys its local work_struct that way... Thanks, Nicolai
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| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Date | 2016-09-23 09:30 +0200 |
| Subject | Re: [PATCH] smp: smp_call_on_cpu(): use INIT_WORK_ONSTACK() for automatic work_struct |
| Message-ID | <skt5M-GK-23@gated-at.bofh.it> |
| In reply to | #1489453 |
On Thu, Sep 22, 2016 at 09:15:52PM +0200, Nicolai Stange wrote: > One minor question regarding your patch though: it hasn't got a > destroy_work_on_stack(). Isn't one needed because of > INIT_WORK_ONSTACK() -> __INIT_WORK() -> __init_work() -> > debug_object_init_on_stack() ? > At least work_on_cpu() destroys its local work_struct that way... I wasn't aware of destroy_work_on_stack(), and I'm not familiar enough with the debug objects stuff to see hwo important it is to call. Also, there's more INIT_WORK_ONSTACK usage lacking destroy_work_on_stack() calls. Maybe it would be good to do a patch fixing them all up and adding a comment with INIT_WORK_ONSTACK() that says it ought to be paired with destroy_work_on_stack().
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