Re: [PATCH -mm] workqueue: debug possible lockups in flush_workqueue
On Thu, Apr 19, 2007 at 08:14:16AM +0200, Ingo Molnar wrote:
>
> * Jarek Poplawski <[EMAIL PROTECTED]> wrote:
>
> > Here is my patch proposal for detecting possible lockups, when
> > flush_workqueue caller holds a lock (e.g. rtnl_lock) also used in work
> > functions.
>
> looks good in principle - did you test it and it caught a bug that wasnt
> caught before?
Yes, but it was only my own testing bug... (I'm not a good tester, sorry).
>
> > +#ifdef CONFIG_PROVE_LOCKING
> > +/* Detect possible flush_workqueue() lockup with circular dependency
> > check. */
> > +static struct lockdep_map flush_dep_map = { .name = "flush_dep_map" };
> > +#endif
>
> > +#ifdef CONFIG_PROVE_LOCKING
> > + /* lockdep dependency: flush_dep_map (read) before any lock: */
> > + lock_acquire(_dep_map, 0, 0, 1, 2, _THIS_IP_);
> > +#endif
>
> i think the #ifdef should only be needed for the .name initialization -
> both lock_acquire() and lock_release() maps to NOP if PROVE_LOCKING is
> off.
There is also DEBUG_LOCK_ALLOC without PROVE_LOCKING possibility,
which isn't usable here.
Jarek P.
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Re: [PATCH -mm] workqueue: debug possible lockups in flush_workqueue
* Jarek Poplawski <[EMAIL PROTECTED]> wrote:
> Here is my patch proposal for detecting possible lockups, when
> flush_workqueue caller holds a lock (e.g. rtnl_lock) also used in work
> functions.
looks good in principle - did you test it and it caught a bug that wasnt
caught before?
> +#ifdef CONFIG_PROVE_LOCKING
> +/* Detect possible flush_workqueue() lockup with circular dependency check.
> */
> +static struct lockdep_map flush_dep_map = { .name = "flush_dep_map" };
> +#endif
> +#ifdef CONFIG_PROVE_LOCKING
> + /* lockdep dependency: flush_dep_map (read) before any lock: */
> + lock_acquire(_dep_map, 0, 0, 1, 2, _THIS_IP_);
> +#endif
i think the #ifdef should only be needed for the .name initialization -
both lock_acquire() and lock_release() maps to NOP if PROVE_LOCKING is
off.
Ingo
-
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Re: [PATCH -mm] workqueue: debug possible lockups in flush_workqueue
* Jarek Poplawski [EMAIL PROTECTED] wrote:
Here is my patch proposal for detecting possible lockups, when
flush_workqueue caller holds a lock (e.g. rtnl_lock) also used in work
functions.
looks good in principle - did you test it and it caught a bug that wasnt
caught before?
+#ifdef CONFIG_PROVE_LOCKING
+/* Detect possible flush_workqueue() lockup with circular dependency check.
*/
+static struct lockdep_map flush_dep_map = { .name = flush_dep_map };
+#endif
+#ifdef CONFIG_PROVE_LOCKING
+ /* lockdep dependency: flush_dep_map (read) before any lock: */
+ lock_acquire(flush_dep_map, 0, 0, 1, 2, _THIS_IP_);
+#endif
i think the #ifdef should only be needed for the .name initialization -
both lock_acquire() and lock_release() maps to NOP if PROVE_LOCKING is
off.
Ingo
-
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the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH -mm] workqueue: debug possible lockups in flush_workqueue
On Thu, Apr 19, 2007 at 08:14:16AM +0200, Ingo Molnar wrote:
* Jarek Poplawski [EMAIL PROTECTED] wrote:
Here is my patch proposal for detecting possible lockups, when
flush_workqueue caller holds a lock (e.g. rtnl_lock) also used in work
functions.
looks good in principle - did you test it and it caught a bug that wasnt
caught before?
Yes, but it was only my own testing bug... (I'm not a good tester, sorry).
+#ifdef CONFIG_PROVE_LOCKING
+/* Detect possible flush_workqueue() lockup with circular dependency
check. */
+static struct lockdep_map flush_dep_map = { .name = flush_dep_map };
+#endif
+#ifdef CONFIG_PROVE_LOCKING
+ /* lockdep dependency: flush_dep_map (read) before any lock: */
+ lock_acquire(flush_dep_map, 0, 0, 1, 2, _THIS_IP_);
+#endif
i think the #ifdef should only be needed for the .name initialization -
both lock_acquire() and lock_release() maps to NOP if PROVE_LOCKING is
off.
There is also DEBUG_LOCK_ALLOC without PROVE_LOCKING possibility,
which isn't usable here.
Jarek P.
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH -mm] workqueue: debug possible lockups in flush_workqueue
Hi,
Here is my patch proposal for detecting possible lockups,
when flush_workqueue caller holds a lock (e.g. rtnl_lock)
also used in work functions.
Regards,
Jarek P.
Signed-off-by: Jarek Poplawski <[EMAIL PROTECTED]>
---
diff -Nurp 2.6.21-rc6-mm1-/kernel/workqueue.c 2.6.21-rc6-mm1/kernel/workqueue.c
--- 2.6.21-rc6-mm1-/kernel/workqueue.c 2007-04-18 20:07:45.0 +0200
+++ 2.6.21-rc6-mm1/kernel/workqueue.c 2007-04-18 21:29:50.0 +0200
@@ -67,6 +67,12 @@ struct workqueue_struct {
/* All the per-cpu workqueues on the system, for hotplug cpu to add/remove
threads to each one as cpus come/go. */
static DEFINE_MUTEX(workqueue_mutex);
+
+#ifdef CONFIG_PROVE_LOCKING
+/* Detect possible flush_workqueue() lockup with circular dependency check. */
+static struct lockdep_map flush_dep_map = { .name = "flush_dep_map" };
+#endif
+
static LIST_HEAD(workqueues);
static int singlethread_cpu __read_mostly;
@@ -247,8 +253,15 @@ static void run_workqueue(struct cpu_wor
BUG_ON(get_wq_data(work) != cwq);
work_clear_pending(work);
+#ifdef CONFIG_PROVE_LOCKING
+ /* lockdep dependency: flush_dep_map (read) before any lock: */
+ lock_acquire(_dep_map, 0, 0, 1, 2, _THIS_IP_);
+#endif
f(work);
+#ifdef CONFIG_PROVE_LOCKING
+ lock_release(_dep_map, 1, _THIS_IP_);
+#endif
if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
"%s/0x%08x/%d\n",
@@ -389,6 +402,14 @@ void fastcall flush_workqueue(struct wor
int cpu;
might_sleep();
+#ifdef CONFIG_PROVE_LOCKING
+ /*
+* Add lockdep dependency: flush_dep_map (exclusive)
+* after any held mutex or rwsem.
+*/
+ lock_acquire(_dep_map, 0, 0, 0, 2, _THIS_IP_);
+ lock_release(_dep_map, 1, _THIS_IP_);
+#endif
for_each_cpu_mask(cpu, *cpu_map)
flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
}
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[PATCH -mm] workqueue: debug possible lockups in flush_workqueue
Hi,
Here is my patch proposal for detecting possible lockups,
when flush_workqueue caller holds a lock (e.g. rtnl_lock)
also used in work functions.
Regards,
Jarek P.
Signed-off-by: Jarek Poplawski [EMAIL PROTECTED]
---
diff -Nurp 2.6.21-rc6-mm1-/kernel/workqueue.c 2.6.21-rc6-mm1/kernel/workqueue.c
--- 2.6.21-rc6-mm1-/kernel/workqueue.c 2007-04-18 20:07:45.0 +0200
+++ 2.6.21-rc6-mm1/kernel/workqueue.c 2007-04-18 21:29:50.0 +0200
@@ -67,6 +67,12 @@ struct workqueue_struct {
/* All the per-cpu workqueues on the system, for hotplug cpu to add/remove
threads to each one as cpus come/go. */
static DEFINE_MUTEX(workqueue_mutex);
+
+#ifdef CONFIG_PROVE_LOCKING
+/* Detect possible flush_workqueue() lockup with circular dependency check. */
+static struct lockdep_map flush_dep_map = { .name = flush_dep_map };
+#endif
+
static LIST_HEAD(workqueues);
static int singlethread_cpu __read_mostly;
@@ -247,8 +253,15 @@ static void run_workqueue(struct cpu_wor
BUG_ON(get_wq_data(work) != cwq);
work_clear_pending(work);
+#ifdef CONFIG_PROVE_LOCKING
+ /* lockdep dependency: flush_dep_map (read) before any lock: */
+ lock_acquire(flush_dep_map, 0, 0, 1, 2, _THIS_IP_);
+#endif
f(work);
+#ifdef CONFIG_PROVE_LOCKING
+ lock_release(flush_dep_map, 1, _THIS_IP_);
+#endif
if (unlikely(in_atomic() || lockdep_depth(current) 0)) {
printk(KERN_ERR BUG: workqueue leaked lock or atomic:
%s/0x%08x/%d\n,
@@ -389,6 +402,14 @@ void fastcall flush_workqueue(struct wor
int cpu;
might_sleep();
+#ifdef CONFIG_PROVE_LOCKING
+ /*
+* Add lockdep dependency: flush_dep_map (exclusive)
+* after any held mutex or rwsem.
+*/
+ lock_acquire(flush_dep_map, 0, 0, 0, 2, _THIS_IP_);
+ lock_release(flush_dep_map, 1, _THIS_IP_);
+#endif
for_each_cpu_mask(cpu, *cpu_map)
flush_cpu_workqueue(per_cpu_ptr(wq-cpu_wq, cpu));
}
-
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