Marek and Guenter reported that commit 287905e68dd2 ("driver core:
Expose device link details in sysfs") caused sleeping/scheduling while
atomic warnings.
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 12, name: kworker/0:1
2 locks held by kworker/0:1/12:
#0: ee8074a8 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
#1: ee921f20 ((work_completion)(&sdp->work)){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
Preemption disabled at:
[<c01b10f0>] srcu_invoke_callbacks+0xc0/0x154
----- 8< ----- SNIP
[<c064590c>] (device_del) from [<c0645c9c>] (device_unregister+0x24/0x64)
[<c0645c9c>] (device_unregister) from [<c01b10fc>] (srcu_invoke_callbacks+0xcc/0x154)
[<c01b10fc>] (srcu_invoke_callbacks) from [<c01493c4>] (process_one_work+0x234/0x7dc)
[<c01493c4>] (process_one_work) from [<c01499b0>] (worker_thread+0x44/0x51c)
[<c01499b0>] (worker_thread) from [<c0150bf4>] (kthread+0x158/0x1a0)
[<c0150bf4>] (kthread) from [<c0100114>] (ret_from_fork+0x14/0x20)
Exception stack(0xee921fb0 to 0xee921ff8)
This was caused by the device link device being released in the context
of srcu_invoke_callbacks(). There is no need to wait till the RCU
callback to release the device link device. So release the device
earlier and move the call_srcu() into the device release code. That way,
the memory will get freed only after the device is released AND the RCU
callback is called.
Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs")
Reported-by: Marek Szyprowski <[email protected]>
Reported-by: Guenter Roeck <[email protected]>
Signed-off-by: Saravana Kannan <[email protected]>
---
v1->v2:
- Better fix
- Changed subject
- v1 is this patch https://lore.kernel.org/lkml/[email protected]/
Marek and Guenter,
I reproduced the original issue and tested this fix. Seems to work for
me. Can you confirm?
Thanks,
Saravana
drivers/base/core.c | 45 +++++++++++++++++++++++++++------------------
1 file changed, 27 insertions(+), 18 deletions(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 5373ddd029f6..ec16b97d45ed 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -306,10 +306,34 @@ static struct attribute *devlink_attrs[] = {
};
ATTRIBUTE_GROUPS(devlink);
+static void device_link_free(struct device_link *link)
+{
+ while (refcount_dec_not_one(&link->rpm_active))
+ pm_runtime_put(link->supplier);
+
+ put_device(link->consumer);
+ put_device(link->supplier);
+ kfree(link);
+}
+
+#ifdef CONFIG_SRCU
+static void __device_link_free_srcu(struct rcu_head *rhead)
+{
+ device_link_free(container_of(rhead, struct device_link, rcu_head));
+}
+
static void devlink_dev_release(struct device *dev)
{
- kfree(to_devlink(dev));
+ struct device_link *link = to_devlink(dev);
+
+ call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
}
+#else
+static void devlink_dev_release(struct device *dev)
+{
+ device_link_free(to_devlink(dev));
+}
+#endif
static struct class devlink_class = {
.name = "devlink",
@@ -730,22 +754,7 @@ static void device_link_add_missing_supplier_links(void)
mutex_unlock(&wfs_lock);
}
-static void device_link_free(struct device_link *link)
-{
- while (refcount_dec_not_one(&link->rpm_active))
- pm_runtime_put(link->supplier);
-
- put_device(link->consumer);
- put_device(link->supplier);
- device_unregister(&link->link_dev);
-}
-
#ifdef CONFIG_SRCU
-static void __device_link_free_srcu(struct rcu_head *rhead)
-{
- device_link_free(container_of(rhead, struct device_link, rcu_head));
-}
-
static void __device_link_del(struct kref *kref)
{
struct device_link *link = container_of(kref, struct device_link, kref);
@@ -758,7 +767,7 @@ static void __device_link_del(struct kref *kref)
list_del_rcu(&link->s_node);
list_del_rcu(&link->c_node);
- call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
+ device_unregister(&link->link_dev);
}
#else /* !CONFIG_SRCU */
static void __device_link_del(struct kref *kref)
@@ -773,7 +782,7 @@ static void __device_link_del(struct kref *kref)
list_del(&link->s_node);
list_del(&link->c_node);
- device_link_free(link);
+ device_unregister(&link->link_dev);
}
#endif /* !CONFIG_SRCU */
--
2.28.0.rc0.105.gf9edc3c819-goog
Hi Saravana,
On 16.07.2020 23:45, Saravana Kannan wrote:
> Marek and Guenter reported that commit 287905e68dd2 ("driver core:
> Expose device link details in sysfs") caused sleeping/scheduling while
> atomic warnings.
>
> BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
> in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 12, name: kworker/0:1
> 2 locks held by kworker/0:1/12:
> #0: ee8074a8 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
> #1: ee921f20 ((work_completion)(&sdp->work)){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
> Preemption disabled at:
> [<c01b10f0>] srcu_invoke_callbacks+0xc0/0x154
> ----- 8< ----- SNIP
> [<c064590c>] (device_del) from [<c0645c9c>] (device_unregister+0x24/0x64)
> [<c0645c9c>] (device_unregister) from [<c01b10fc>] (srcu_invoke_callbacks+0xcc/0x154)
> [<c01b10fc>] (srcu_invoke_callbacks) from [<c01493c4>] (process_one_work+0x234/0x7dc)
> [<c01493c4>] (process_one_work) from [<c01499b0>] (worker_thread+0x44/0x51c)
> [<c01499b0>] (worker_thread) from [<c0150bf4>] (kthread+0x158/0x1a0)
> [<c0150bf4>] (kthread) from [<c0100114>] (ret_from_fork+0x14/0x20)
> Exception stack(0xee921fb0 to 0xee921ff8)
>
> This was caused by the device link device being released in the context
> of srcu_invoke_callbacks(). There is no need to wait till the RCU
> callback to release the device link device. So release the device
> earlier and move the call_srcu() into the device release code. That way,
> the memory will get freed only after the device is released AND the RCU
> callback is called.
>
> Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs")
> Reported-by: Marek Szyprowski <[email protected]>
> Reported-by: Guenter Roeck <[email protected]>
> Signed-off-by: Saravana Kannan <[email protected]>
> ---
>
> v1->v2:
> - Better fix
> - Changed subject
> - v1 is this patch https://lore.kernel.org/lkml/[email protected]/
>
> Marek and Guenter,
>
> I reproduced the original issue and tested this fix. Seems to work for
> me. Can you confirm?
Confirmed, this one fixes the issue! :)
Tested-by: Marek Szyprowski <[email protected]>
> Thanks,
> Saravana
>
> drivers/base/core.c | 45 +++++++++++++++++++++++++++------------------
> 1 file changed, 27 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 5373ddd029f6..ec16b97d45ed 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -306,10 +306,34 @@ static struct attribute *devlink_attrs[] = {
> };
> ATTRIBUTE_GROUPS(devlink);
>
> +static void device_link_free(struct device_link *link)
> +{
> + while (refcount_dec_not_one(&link->rpm_active))
> + pm_runtime_put(link->supplier);
> +
> + put_device(link->consumer);
> + put_device(link->supplier);
> + kfree(link);
> +}
> +
> +#ifdef CONFIG_SRCU
> +static void __device_link_free_srcu(struct rcu_head *rhead)
> +{
> + device_link_free(container_of(rhead, struct device_link, rcu_head));
> +}
> +
> static void devlink_dev_release(struct device *dev)
> {
> - kfree(to_devlink(dev));
> + struct device_link *link = to_devlink(dev);
> +
> + call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
> }
> +#else
> +static void devlink_dev_release(struct device *dev)
> +{
> + device_link_free(to_devlink(dev));
> +}
> +#endif
>
> static struct class devlink_class = {
> .name = "devlink",
> @@ -730,22 +754,7 @@ static void device_link_add_missing_supplier_links(void)
> mutex_unlock(&wfs_lock);
> }
>
> -static void device_link_free(struct device_link *link)
> -{
> - while (refcount_dec_not_one(&link->rpm_active))
> - pm_runtime_put(link->supplier);
> -
> - put_device(link->consumer);
> - put_device(link->supplier);
> - device_unregister(&link->link_dev);
> -}
> -
> #ifdef CONFIG_SRCU
> -static void __device_link_free_srcu(struct rcu_head *rhead)
> -{
> - device_link_free(container_of(rhead, struct device_link, rcu_head));
> -}
> -
> static void __device_link_del(struct kref *kref)
> {
> struct device_link *link = container_of(kref, struct device_link, kref);
> @@ -758,7 +767,7 @@ static void __device_link_del(struct kref *kref)
>
> list_del_rcu(&link->s_node);
> list_del_rcu(&link->c_node);
> - call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
> + device_unregister(&link->link_dev);
> }
> #else /* !CONFIG_SRCU */
> static void __device_link_del(struct kref *kref)
> @@ -773,7 +782,7 @@ static void __device_link_del(struct kref *kref)
>
> list_del(&link->s_node);
> list_del(&link->c_node);
> - device_link_free(link);
> + device_unregister(&link->link_dev);
> }
> #endif /* !CONFIG_SRCU */
>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
On Thu, Jul 16, 2020 at 3:13 PM Marek Szyprowski
<[email protected]> wrote:
>
> Hi Saravana,
>
> On 16.07.2020 23:45, Saravana Kannan wrote:
> > Marek and Guenter reported that commit 287905e68dd2 ("driver core:
> > Expose device link details in sysfs") caused sleeping/scheduling while
> > atomic warnings.
> >
> > BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
> > in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 12, name: kworker/0:1
> > 2 locks held by kworker/0:1/12:
> > #0: ee8074a8 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
> > #1: ee921f20 ((work_completion)(&sdp->work)){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
> > Preemption disabled at:
> > [<c01b10f0>] srcu_invoke_callbacks+0xc0/0x154
> > ----- 8< ----- SNIP
> > [<c064590c>] (device_del) from [<c0645c9c>] (device_unregister+0x24/0x64)
> > [<c0645c9c>] (device_unregister) from [<c01b10fc>] (srcu_invoke_callbacks+0xcc/0x154)
> > [<c01b10fc>] (srcu_invoke_callbacks) from [<c01493c4>] (process_one_work+0x234/0x7dc)
> > [<c01493c4>] (process_one_work) from [<c01499b0>] (worker_thread+0x44/0x51c)
> > [<c01499b0>] (worker_thread) from [<c0150bf4>] (kthread+0x158/0x1a0)
> > [<c0150bf4>] (kthread) from [<c0100114>] (ret_from_fork+0x14/0x20)
> > Exception stack(0xee921fb0 to 0xee921ff8)
> >
> > This was caused by the device link device being released in the context
> > of srcu_invoke_callbacks(). There is no need to wait till the RCU
> > callback to release the device link device. So release the device
> > earlier and move the call_srcu() into the device release code. That way,
> > the memory will get freed only after the device is released AND the RCU
> > callback is called.
> >
> > Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs")
> > Reported-by: Marek Szyprowski <[email protected]>
> > Reported-by: Guenter Roeck <[email protected]>
> > Signed-off-by: Saravana Kannan <[email protected]>
> > ---
> >
> > v1->v2:
> > - Better fix
> > - Changed subject
> > - v1 is this patch https://lore.kernel.org/lkml/[email protected]/
> >
> > Marek and Guenter,
> >
> > I reproduced the original issue and tested this fix. Seems to work for
> > me. Can you confirm?
>
> Confirmed, this one fixes the issue! :)
>
> Tested-by: Marek Szyprowski <[email protected]>
Thanks!
-Saravana
On Fri, Jul 17, 2020 at 12:13:04AM +0200, Marek Szyprowski wrote:
> Hi Saravana,
>
> On 16.07.2020 23:45, Saravana Kannan wrote:
> > Marek and Guenter reported that commit 287905e68dd2 ("driver core:
> > Expose device link details in sysfs") caused sleeping/scheduling while
> > atomic warnings.
> >
> > BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
> > in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 12, name: kworker/0:1
> > 2 locks held by kworker/0:1/12:
> > #0: ee8074a8 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
> > #1: ee921f20 ((work_completion)(&sdp->work)){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
> > Preemption disabled at:
> > [<c01b10f0>] srcu_invoke_callbacks+0xc0/0x154
> > ----- 8< ----- SNIP
> > [<c064590c>] (device_del) from [<c0645c9c>] (device_unregister+0x24/0x64)
> > [<c0645c9c>] (device_unregister) from [<c01b10fc>] (srcu_invoke_callbacks+0xcc/0x154)
> > [<c01b10fc>] (srcu_invoke_callbacks) from [<c01493c4>] (process_one_work+0x234/0x7dc)
> > [<c01493c4>] (process_one_work) from [<c01499b0>] (worker_thread+0x44/0x51c)
> > [<c01499b0>] (worker_thread) from [<c0150bf4>] (kthread+0x158/0x1a0)
> > [<c0150bf4>] (kthread) from [<c0100114>] (ret_from_fork+0x14/0x20)
> > Exception stack(0xee921fb0 to 0xee921ff8)
> >
> > This was caused by the device link device being released in the context
> > of srcu_invoke_callbacks(). There is no need to wait till the RCU
> > callback to release the device link device. So release the device
> > earlier and move the call_srcu() into the device release code. That way,
> > the memory will get freed only after the device is released AND the RCU
> > callback is called.
> >
> > Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs")
> > Reported-by: Marek Szyprowski <[email protected]>
> > Reported-by: Guenter Roeck <[email protected]>
> > Signed-off-by: Saravana Kannan <[email protected]>
> > ---
> >
> > v1->v2:
> > - Better fix
> > - Changed subject
> > - v1 is this patch https://lore.kernel.org/lkml/[email protected]/
> >
> > Marek and Guenter,
> >
> > I reproduced the original issue and tested this fix. Seems to work for
> > me. Can you confirm?
>
> Confirmed, this one fixes the issue! :)
>
Same here.
Tested-by: Guenter Roeck <[email protected]>
Guenter
> Tested-by: Marek Szyprowski <[email protected]>
>
> > Thanks,
> > Saravana
> >
> > drivers/base/core.c | 45 +++++++++++++++++++++++++++------------------
> > 1 file changed, 27 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/base/core.c b/drivers/base/core.c
> > index 5373ddd029f6..ec16b97d45ed 100644
> > --- a/drivers/base/core.c
> > +++ b/drivers/base/core.c
> > @@ -306,10 +306,34 @@ static struct attribute *devlink_attrs[] = {
> > };
> > ATTRIBUTE_GROUPS(devlink);
> >
> > +static void device_link_free(struct device_link *link)
> > +{
> > + while (refcount_dec_not_one(&link->rpm_active))
> > + pm_runtime_put(link->supplier);
> > +
> > + put_device(link->consumer);
> > + put_device(link->supplier);
> > + kfree(link);
> > +}
> > +
> > +#ifdef CONFIG_SRCU
> > +static void __device_link_free_srcu(struct rcu_head *rhead)
> > +{
> > + device_link_free(container_of(rhead, struct device_link, rcu_head));
> > +}
> > +
> > static void devlink_dev_release(struct device *dev)
> > {
> > - kfree(to_devlink(dev));
> > + struct device_link *link = to_devlink(dev);
> > +
> > + call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
> > }
> > +#else
> > +static void devlink_dev_release(struct device *dev)
> > +{
> > + device_link_free(to_devlink(dev));
> > +}
> > +#endif
> >
> > static struct class devlink_class = {
> > .name = "devlink",
> > @@ -730,22 +754,7 @@ static void device_link_add_missing_supplier_links(void)
> > mutex_unlock(&wfs_lock);
> > }
> >
> > -static void device_link_free(struct device_link *link)
> > -{
> > - while (refcount_dec_not_one(&link->rpm_active))
> > - pm_runtime_put(link->supplier);
> > -
> > - put_device(link->consumer);
> > - put_device(link->supplier);
> > - device_unregister(&link->link_dev);
> > -}
> > -
> > #ifdef CONFIG_SRCU
> > -static void __device_link_free_srcu(struct rcu_head *rhead)
> > -{
> > - device_link_free(container_of(rhead, struct device_link, rcu_head));
> > -}
> > -
> > static void __device_link_del(struct kref *kref)
> > {
> > struct device_link *link = container_of(kref, struct device_link, kref);
> > @@ -758,7 +767,7 @@ static void __device_link_del(struct kref *kref)
> >
> > list_del_rcu(&link->s_node);
> > list_del_rcu(&link->c_node);
> > - call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
> > + device_unregister(&link->link_dev);
> > }
> > #else /* !CONFIG_SRCU */
> > static void __device_link_del(struct kref *kref)
> > @@ -773,7 +782,7 @@ static void __device_link_del(struct kref *kref)
> >
> > list_del(&link->s_node);
> > list_del(&link->c_node);
> > - device_link_free(link);
> > + device_unregister(&link->link_dev);
> > }
> > #endif /* !CONFIG_SRCU */
> >
>
> Best regards
> --
> Marek Szyprowski, PhD
> Samsung R&D Institute Poland
>
On Fri, Jul 17, 2020 at 9:34 AM Guenter Roeck <[email protected]> wrote:
>
> On Fri, Jul 17, 2020 at 12:13:04AM +0200, Marek Szyprowski wrote:
> > Hi Saravana,
> >
> > On 16.07.2020 23:45, Saravana Kannan wrote:
> > > Marek and Guenter reported that commit 287905e68dd2 ("driver core:
> > > Expose device link details in sysfs") caused sleeping/scheduling while
> > > atomic warnings.
> > >
> > > BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
> > > in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 12, name: kworker/0:1
> > > 2 locks held by kworker/0:1/12:
> > > #0: ee8074a8 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
> > > #1: ee921f20 ((work_completion)(&sdp->work)){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
> > > Preemption disabled at:
> > > [<c01b10f0>] srcu_invoke_callbacks+0xc0/0x154
> > > ----- 8< ----- SNIP
> > > [<c064590c>] (device_del) from [<c0645c9c>] (device_unregister+0x24/0x64)
> > > [<c0645c9c>] (device_unregister) from [<c01b10fc>] (srcu_invoke_callbacks+0xcc/0x154)
> > > [<c01b10fc>] (srcu_invoke_callbacks) from [<c01493c4>] (process_one_work+0x234/0x7dc)
> > > [<c01493c4>] (process_one_work) from [<c01499b0>] (worker_thread+0x44/0x51c)
> > > [<c01499b0>] (worker_thread) from [<c0150bf4>] (kthread+0x158/0x1a0)
> > > [<c0150bf4>] (kthread) from [<c0100114>] (ret_from_fork+0x14/0x20)
> > > Exception stack(0xee921fb0 to 0xee921ff8)
> > >
> > > This was caused by the device link device being released in the context
> > > of srcu_invoke_callbacks(). There is no need to wait till the RCU
> > > callback to release the device link device. So release the device
> > > earlier and move the call_srcu() into the device release code. That way,
> > > the memory will get freed only after the device is released AND the RCU
> > > callback is called.
> > >
> > > Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs")
> > > Reported-by: Marek Szyprowski <[email protected]>
> > > Reported-by: Guenter Roeck <[email protected]>
> > > Signed-off-by: Saravana Kannan <[email protected]>
> > > ---
> > >
> > > v1->v2:
> > > - Better fix
> > > - Changed subject
> > > - v1 is this patch https://lore.kernel.org/lkml/[email protected]/
> > >
> > > Marek and Guenter,
> > >
> > > I reproduced the original issue and tested this fix. Seems to work for
> > > me. Can you confirm?
> >
> > Confirmed, this one fixes the issue! :)
> >
> Same here.
>
> Tested-by: Guenter Roeck <[email protected]>
>
> Guenter
>
> > Tested-by: Marek Szyprowski <[email protected]>
> >
Thanks both.
Greg, can you review this and pull this into driver-core-next too?
-Saravana