| Message ID | 20130411204104.GC11956@mtj.dyndns.org |
|---|---|
| State | Not Applicable |
| Headers | show |
On Thu, Apr 11, 2013 at 11:41 PM, Tejun Heo <tj@kernel.org> wrote: > Hello, > > On Thu, Apr 11, 2013 at 11:30:53PM +0300, Michael S. Tsirkin wrote: >> Okay, so you are saying it's a false-positive? > > Yeah, I think so. It didn't actually lock up, right? It it did, > our analysis upto this point is likely to be completely wrong. > >> Want to send a patch so Or can try it out? I can test that Sunday > > Hmmm... something like the following on the workqueue side (completely > untested). > > diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h > index 8afab27..899d470 100644 > --- a/include/linux/workqueue.h > +++ b/include/linux/workqueue.h > @@ -466,14 +466,21 @@ static inline bool __deprecated flush_delayed_work_sync(struct delayed_work *dwo > } > > #ifndef CONFIG_SMP > -static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) > +static inline long work_on_cpu_nested(unsigned int cpu, long (*fn)(void *), > + void *arg, int subclass) > { > return fn(arg); > } > #else > -long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg); > +long work_on_cpu_nested(unsigned int cpu, long (*fn)(void *), void *arg, > + int subclass); > #endif /* CONFIG_SMP */ > > +static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) > +{ > + return work_on_cpu_nested(cpu, fn, arg, 0); > +} > + > #ifdef CONFIG_FREEZER > extern void freeze_workqueues_begin(void); > extern bool freeze_workqueues_busy(void); > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 81f2457..c2be670 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -3555,25 +3555,30 @@ static void work_for_cpu_fn(struct work_struct *work) > } > > /** > - * work_on_cpu - run a function in user context on a particular cpu > + * work_on_cpu_nested - run a function in user context on a particular cpu > * @cpu: the cpu to run on > * @fn: the function to run > * @arg: the function arg > + * @subclass: lockdep subclass > * > * This will return the value @fn returns. > * It is up to the caller to ensure that the cpu doesn't go offline. > * The caller must not hold any locks which would prevent @fn from completing. > + * > + * XXX: explain @subclass > */ > -long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) > +long work_on_cpu_nested(unsigned int cpu, long (*fn)(void *), void *arg, > + int subclass) > { > struct work_for_cpu wfc = { .fn = fn, .arg = arg }; > > INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn); > + lock_set_subclass(&wfc.work.lockdep_map, subclass, _RET_IP_); > schedule_work_on(cpu, &wfc.work); > flush_work(&wfc.work); > return wfc.ret; > } > -EXPORT_SYMBOL_GPL(work_on_cpu); > +EXPORT_SYMBOL_GPL(work_on_cpu_nested); > #endif /* CONFIG_SMP */ > > #ifdef CONFIG_FREEZER > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, Apr 14, 2013 at 03:58:55PM +0300, Or Gerlitz wrote: > So the patch eliminated the lockdep warning for mlx4 nested probing > sequence, but introduced lockdep warning for > 00:13.0 PIC: Intel Corporation 7500/5520/5500/X58 I/O Hub I/OxAPIC > Interrupt Controller (rev 22) Oops, the patch in itself doesn't really change anything. The caller should use a different subclass for the nested invocation, just like spin_lock_nested() and friends. Sorry about not being clear. Michael, can you please help? Thanks.
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 8afab27..899d470 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -466,14 +466,21 @@ static inline bool __deprecated flush_delayed_work_sync(struct delayed_work *dwo } #ifndef CONFIG_SMP -static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) +static inline long work_on_cpu_nested(unsigned int cpu, long (*fn)(void *), + void *arg, int subclass) { return fn(arg); } #else -long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg); +long work_on_cpu_nested(unsigned int cpu, long (*fn)(void *), void *arg, + int subclass); #endif /* CONFIG_SMP */ +static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) +{ + return work_on_cpu_nested(cpu, fn, arg, 0); +} + #ifdef CONFIG_FREEZER extern void freeze_workqueues_begin(void); extern bool freeze_workqueues_busy(void); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 81f2457..c2be670 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3555,25 +3555,30 @@ static void work_for_cpu_fn(struct work_struct *work) } /** - * work_on_cpu - run a function in user context on a particular cpu + * work_on_cpu_nested - run a function in user context on a particular cpu * @cpu: the cpu to run on * @fn: the function to run * @arg: the function arg + * @subclass: lockdep subclass * * This will return the value @fn returns. * It is up to the caller to ensure that the cpu doesn't go offline. * The caller must not hold any locks which would prevent @fn from completing. + * + * XXX: explain @subclass */ -long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) +long work_on_cpu_nested(unsigned int cpu, long (*fn)(void *), void *arg, + int subclass) { struct work_for_cpu wfc = { .fn = fn, .arg = arg }; INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn); + lock_set_subclass(&wfc.work.lockdep_map, subclass, _RET_IP_); schedule_work_on(cpu, &wfc.work); flush_work(&wfc.work); return wfc.ret; } -EXPORT_SYMBOL_GPL(work_on_cpu); +EXPORT_SYMBOL_GPL(work_on_cpu_nested); #endif /* CONFIG_SMP */ #ifdef CONFIG_FREEZER