This patch fixes the lockdep warning below
[ 7.229767] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
[ 7.229776] ------------[ cut here ]------------
[ 7.229787] WARNING: CPU: 1 PID: 1 at linux-next/kernel/locking/lockdep.c:2876 loc
kdep_trace_alloc+0xe0/0xf0
[ 7.229790] Modules linked in:
[ 7.229793]
[ 7.229798] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.8.0-11756-g86c5152 #46
...
[ 7.229900] Call trace:
[ 7.229903] Exception stack(0xffff8007da837890 to 0xffff8007da8379c0)
[ 7.229906] 7880: ffff8007da834000 0001000000000000
[ 7.229909] 78a0: ffff8007da837a70 ffff0000081111a0 00000000600000c5 000000000000003d
[ 7.229912] 78c0: 9374bc6a7f3c7832 0000000000381878 ffff000009db7ab8 000000000000002f
[ 7.229915] 78e0: ffff00000811aabc ffff000008be2548 ffff8007da837990 ffff00000811adf8
[ 7.229918] 7900: ffff8007da834000 00000000024080c0 00000000000000c0 ffff000009021000
[ 7.229921] 7920: 0000000000000000 0000000000000000 ffff000008c8f7c8 ffff8007da579810
[ 7.229923] 7940: 000000000000002f ffff8007da858000 0000000000000000 0000000000000001
[ 7.229926] 7960: 0000000000000001 0000000000000000 ffff00000811a468 0000000000000002
[ 7.229929] 7980: 656c62617369645f 0000000000038187 00000000000000ee ffff8007da837850
[ 7.229932] 79a0: ffff000009db50c0 ffff000009db569d 0000000000000006 ffff000089db568f
[ 7.229936] [<ffff0000081111a0>] lockdep_trace_alloc+0xe0/0xf0
[ 7.229940] [<ffff0000081f4950>] __kmalloc_track_caller+0x50/0x250
[ 7.229945] [<ffff00000857c088>] devres_alloc_node+0x28/0x60
[ 7.229949] [<ffff0000081220e0>] devm_request_threaded_irq+0x50/0xe0
[ 7.229955] [<ffff0000087e6220>] pcc_mbox_request_channel+0x110/0x170
[ 7.229960] [<ffff0000084b2660>] acpi_cppc_processor_probe+0x264/0x414
[ 7.229963] [<ffff0000084ae9f4>] __acpi_processor_start+0x28/0xa0
[ 7.229966] [<ffff0000084aeab0>] acpi_processor_start+0x44/0x54
[ 7.229970] [<ffff00000857897c>] driver_probe_device+0x1fc/0x2b0
[ 7.229974] [<ffff000008578ae4>] __driver_attach+0xb4/0xc0
[ 7.229977] [<ffff00000857683c>] bus_for_each_dev+0x5c/0xa0
[ 7.229980] [<ffff000008578110>] driver_attach+0x20/0x30
[ 7.229983] [<ffff000008577c20>] bus_add_driver+0x110/0x230
[ 7.229987] [<ffff000008579320>] driver_register+0x60/0x100
[ 7.229991] [<ffff000008d478b8>] acpi_processor_driver_init+0x2c/0xb0
[ 7.229996] [<ffff000008083168>] do_one_initcall+0x38/0x130
[ 7.230000] [<ffff000008d20d6c>] kernel_init_freeable+0x210/0x2b4
[ 7.230004] [<ffff000008945d90>] kernel_init+0x10/0x110
[ 7.230007] [<ffff000008082e80>] ret_from_fork+0x10/0x50
It's because the spinlock inside pcc_mbox_request_channel() is
kept too long. This patch releases spinlock before request_irq()
and free_irq() to fix this issue as spinlock is only needed to
protect the channel data.
Signed-off-by: Hoan Tran <[email protected]>
---
v3
* Free mailbox irq before reset the channel data
* Free channel if it fails to request the mailbox irq
v2
* Release spinlock before request_irq() and free_irq() instead of
using mutex
drivers/mailbox/pcc.c | 70 +++++++++++++++++++++++++--------------------------
1 file changed, 35 insertions(+), 35 deletions(-)
diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index 08c87fa..4b2f061 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -224,6 +224,38 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
}
/**
+ * pcc_mbox_free_channel - Clients call this to free their Channel.
+ *
+ * @chan: Pointer to the mailbox channel as returned by
+ * pcc_mbox_request_channel()
+ */
+void pcc_mbox_free_channel(struct mbox_chan *chan)
+{
+ u32 id = chan - pcc_mbox_channels;
+ unsigned long flags;
+
+ if (!chan || !chan->cl)
+ return;
+
+ if (id >= pcc_mbox_ctrl.num_chans) {
+ pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
+ return;
+ }
+
+ if (pcc_doorbell_irq[id] > 0)
+ devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
+
+ spin_lock_irqsave(&chan->lock, flags);
+ chan->cl = NULL;
+ chan->active_req = NULL;
+ if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
+ chan->txdone_method = TXDONE_BY_POLL;
+
+ spin_unlock_irqrestore(&chan->lock, flags);
+}
+EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
+
+/**
* pcc_mbox_request_channel - PCC clients call this function to
* request a pointer to their PCC subspace, from which they
* can get the details of communicating with the remote.
@@ -267,6 +299,8 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
chan->txdone_method |= TXDONE_BY_ACK;
+ spin_unlock_irqrestore(&chan->lock, flags);
+
if (pcc_doorbell_irq[subspace_id] > 0) {
int rc;
@@ -275,50 +309,16 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
if (unlikely(rc)) {
dev_err(dev, "failed to register PCC interrupt %d\n",
pcc_doorbell_irq[subspace_id]);
+ pcc_mbox_free_channel(chan);
chan = ERR_PTR(rc);
}
}
- spin_unlock_irqrestore(&chan->lock, flags);
-
return chan;
}
EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
/**
- * pcc_mbox_free_channel - Clients call this to free their Channel.
- *
- * @chan: Pointer to the mailbox channel as returned by
- * pcc_mbox_request_channel()
- */
-void pcc_mbox_free_channel(struct mbox_chan *chan)
-{
- u32 id = chan - pcc_mbox_channels;
- unsigned long flags;
-
- if (!chan || !chan->cl)
- return;
-
- if (id >= pcc_mbox_ctrl.num_chans) {
- pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
- return;
- }
-
- spin_lock_irqsave(&chan->lock, flags);
- chan->cl = NULL;
- chan->active_req = NULL;
- if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
- chan->txdone_method = TXDONE_BY_POLL;
-
- if (pcc_doorbell_irq[id] > 0)
- devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
-
- spin_unlock_irqrestore(&chan->lock, flags);
-}
-EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
-
-
-/**
* pcc_send_data - Called from Mailbox Controller code. Used
* here only to ring the channel doorbell. The PCC client
* specific read/write is done in the client driver in
--
1.9.1
Hi All,
On Thu, Oct 27, 2016 at 3:34 PM, Hoan Tran <[email protected]> wrote:
> This patch fixes the lockdep warning below
>
> [ 7.229767] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
> [ 7.229776] ------------[ cut here ]------------
> [ 7.229787] WARNING: CPU: 1 PID: 1 at linux-next/kernel/locking/lockdep.c:2876 loc
> kdep_trace_alloc+0xe0/0xf0
> [ 7.229790] Modules linked in:
> [ 7.229793]
> [ 7.229798] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.8.0-11756-g86c5152 #46
> ...
> [ 7.229900] Call trace:
> [ 7.229903] Exception stack(0xffff8007da837890 to 0xffff8007da8379c0)
> [ 7.229906] 7880: ffff8007da834000 0001000000000000
> [ 7.229909] 78a0: ffff8007da837a70 ffff0000081111a0 00000000600000c5 000000000000003d
> [ 7.229912] 78c0: 9374bc6a7f3c7832 0000000000381878 ffff000009db7ab8 000000000000002f
> [ 7.229915] 78e0: ffff00000811aabc ffff000008be2548 ffff8007da837990 ffff00000811adf8
> [ 7.229918] 7900: ffff8007da834000 00000000024080c0 00000000000000c0 ffff000009021000
> [ 7.229921] 7920: 0000000000000000 0000000000000000 ffff000008c8f7c8 ffff8007da579810
> [ 7.229923] 7940: 000000000000002f ffff8007da858000 0000000000000000 0000000000000001
> [ 7.229926] 7960: 0000000000000001 0000000000000000 ffff00000811a468 0000000000000002
> [ 7.229929] 7980: 656c62617369645f 0000000000038187 00000000000000ee ffff8007da837850
> [ 7.229932] 79a0: ffff000009db50c0 ffff000009db569d 0000000000000006 ffff000089db568f
> [ 7.229936] [<ffff0000081111a0>] lockdep_trace_alloc+0xe0/0xf0
> [ 7.229940] [<ffff0000081f4950>] __kmalloc_track_caller+0x50/0x250
> [ 7.229945] [<ffff00000857c088>] devres_alloc_node+0x28/0x60
> [ 7.229949] [<ffff0000081220e0>] devm_request_threaded_irq+0x50/0xe0
> [ 7.229955] [<ffff0000087e6220>] pcc_mbox_request_channel+0x110/0x170
> [ 7.229960] [<ffff0000084b2660>] acpi_cppc_processor_probe+0x264/0x414
> [ 7.229963] [<ffff0000084ae9f4>] __acpi_processor_start+0x28/0xa0
> [ 7.229966] [<ffff0000084aeab0>] acpi_processor_start+0x44/0x54
> [ 7.229970] [<ffff00000857897c>] driver_probe_device+0x1fc/0x2b0
> [ 7.229974] [<ffff000008578ae4>] __driver_attach+0xb4/0xc0
> [ 7.229977] [<ffff00000857683c>] bus_for_each_dev+0x5c/0xa0
> [ 7.229980] [<ffff000008578110>] driver_attach+0x20/0x30
> [ 7.229983] [<ffff000008577c20>] bus_add_driver+0x110/0x230
> [ 7.229987] [<ffff000008579320>] driver_register+0x60/0x100
> [ 7.229991] [<ffff000008d478b8>] acpi_processor_driver_init+0x2c/0xb0
> [ 7.229996] [<ffff000008083168>] do_one_initcall+0x38/0x130
> [ 7.230000] [<ffff000008d20d6c>] kernel_init_freeable+0x210/0x2b4
> [ 7.230004] [<ffff000008945d90>] kernel_init+0x10/0x110
> [ 7.230007] [<ffff000008082e80>] ret_from_fork+0x10/0x50
>
> It's because the spinlock inside pcc_mbox_request_channel() is
> kept too long. This patch releases spinlock before request_irq()
> and free_irq() to fix this issue as spinlock is only needed to
> protect the channel data.
>
> Signed-off-by: Hoan Tran <[email protected]>
> ---
> v3
> * Free mailbox irq before reset the channel data
> * Free channel if it fails to request the mailbox irq
>
> v2
> * Release spinlock before request_irq() and free_irq() instead of
> using mutex
>
>
> drivers/mailbox/pcc.c | 70 +++++++++++++++++++++++++--------------------------
> 1 file changed, 35 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
> index 08c87fa..4b2f061 100644
> --- a/drivers/mailbox/pcc.c
> +++ b/drivers/mailbox/pcc.c
> @@ -224,6 +224,38 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
> }
>
> /**
> + * pcc_mbox_free_channel - Clients call this to free their Channel.
> + *
> + * @chan: Pointer to the mailbox channel as returned by
> + * pcc_mbox_request_channel()
> + */
> +void pcc_mbox_free_channel(struct mbox_chan *chan)
> +{
> + u32 id = chan - pcc_mbox_channels;
> + unsigned long flags;
> +
> + if (!chan || !chan->cl)
> + return;
> +
> + if (id >= pcc_mbox_ctrl.num_chans) {
> + pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
> + return;
> + }
> +
> + if (pcc_doorbell_irq[id] > 0)
> + devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
> +
> + spin_lock_irqsave(&chan->lock, flags);
> + chan->cl = NULL;
> + chan->active_req = NULL;
> + if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
> + chan->txdone_method = TXDONE_BY_POLL;
> +
> + spin_unlock_irqrestore(&chan->lock, flags);
> +}
> +EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
> +
> +/**
> * pcc_mbox_request_channel - PCC clients call this function to
> * request a pointer to their PCC subspace, from which they
> * can get the details of communicating with the remote.
> @@ -267,6 +299,8 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
> if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
> chan->txdone_method |= TXDONE_BY_ACK;
>
> + spin_unlock_irqrestore(&chan->lock, flags);
> +
> if (pcc_doorbell_irq[subspace_id] > 0) {
> int rc;
>
> @@ -275,50 +309,16 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
> if (unlikely(rc)) {
> dev_err(dev, "failed to register PCC interrupt %d\n",
> pcc_doorbell_irq[subspace_id]);
> + pcc_mbox_free_channel(chan);
> chan = ERR_PTR(rc);
> }
> }
>
> - spin_unlock_irqrestore(&chan->lock, flags);
> -
> return chan;
> }
> EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
>
> /**
> - * pcc_mbox_free_channel - Clients call this to free their Channel.
> - *
> - * @chan: Pointer to the mailbox channel as returned by
> - * pcc_mbox_request_channel()
> - */
> -void pcc_mbox_free_channel(struct mbox_chan *chan)
> -{
> - u32 id = chan - pcc_mbox_channels;
> - unsigned long flags;
> -
> - if (!chan || !chan->cl)
> - return;
> -
> - if (id >= pcc_mbox_ctrl.num_chans) {
> - pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
> - return;
> - }
> -
> - spin_lock_irqsave(&chan->lock, flags);
> - chan->cl = NULL;
> - chan->active_req = NULL;
> - if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
> - chan->txdone_method = TXDONE_BY_POLL;
> -
> - if (pcc_doorbell_irq[id] > 0)
> - devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
> -
> - spin_unlock_irqrestore(&chan->lock, flags);
> -}
> -EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
> -
> -
> -/**
> * pcc_send_data - Called from Mailbox Controller code. Used
> * here only to ring the channel doorbell. The PCC client
> * specific read/write is done in the client driver in
> --
> 1.9.1
>
Do you have any comments about this patch ?
Thanks
Hoan
HI Hoan,
On 11/9/2016 11:39 PM, Hoan Tran wrote:
> Hi All,
>
> On Thu, Oct 27, 2016 at 3:34 PM, Hoan Tran <[email protected]> wrote:
>> This patch fixes the lockdep warning below
>>
>> [ 7.229767] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
>> [ 7.229776] ------------[ cut here ]------------
>> [ 7.229787] WARNING: CPU: 1 PID: 1 at linux-next/kernel/locking/lockdep.c:2876 loc
>> kdep_trace_alloc+0xe0/0xf0
>> [ 7.229790] Modules linked in:
>> [ 7.229793]
>> [ 7.229798] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.8.0-11756-g86c5152 #46
>> ...
>> [ 7.229900] Call trace:
>> [ 7.229903] Exception stack(0xffff8007da837890 to 0xffff8007da8379c0)
>> [ 7.229906] 7880: ffff8007da834000 0001000000000000
>> [ 7.229909] 78a0: ffff8007da837a70 ffff0000081111a0 00000000600000c5 000000000000003d
>> [ 7.229912] 78c0: 9374bc6a7f3c7832 0000000000381878 ffff000009db7ab8 000000000000002f
>> [ 7.229915] 78e0: ffff00000811aabc ffff000008be2548 ffff8007da837990 ffff00000811adf8
>> [ 7.229918] 7900: ffff8007da834000 00000000024080c0 00000000000000c0 ffff000009021000
>> [ 7.229921] 7920: 0000000000000000 0000000000000000 ffff000008c8f7c8 ffff8007da579810
>> [ 7.229923] 7940: 000000000000002f ffff8007da858000 0000000000000000 0000000000000001
>> [ 7.229926] 7960: 0000000000000001 0000000000000000 ffff00000811a468 0000000000000002
>> [ 7.229929] 7980: 656c62617369645f 0000000000038187 00000000000000ee ffff8007da837850
>> [ 7.229932] 79a0: ffff000009db50c0 ffff000009db569d 0000000000000006 ffff000089db568f
>> [ 7.229936] [<ffff0000081111a0>] lockdep_trace_alloc+0xe0/0xf0
>> [ 7.229940] [<ffff0000081f4950>] __kmalloc_track_caller+0x50/0x250
>> [ 7.229945] [<ffff00000857c088>] devres_alloc_node+0x28/0x60
>> [ 7.229949] [<ffff0000081220e0>] devm_request_threaded_irq+0x50/0xe0
>> [ 7.229955] [<ffff0000087e6220>] pcc_mbox_request_channel+0x110/0x170
>> [ 7.229960] [<ffff0000084b2660>] acpi_cppc_processor_probe+0x264/0x414
>> [ 7.229963] [<ffff0000084ae9f4>] __acpi_processor_start+0x28/0xa0
>> [ 7.229966] [<ffff0000084aeab0>] acpi_processor_start+0x44/0x54
>> [ 7.229970] [<ffff00000857897c>] driver_probe_device+0x1fc/0x2b0
>> [ 7.229974] [<ffff000008578ae4>] __driver_attach+0xb4/0xc0
>> [ 7.229977] [<ffff00000857683c>] bus_for_each_dev+0x5c/0xa0
>> [ 7.229980] [<ffff000008578110>] driver_attach+0x20/0x30
>> [ 7.229983] [<ffff000008577c20>] bus_add_driver+0x110/0x230
>> [ 7.229987] [<ffff000008579320>] driver_register+0x60/0x100
>> [ 7.229991] [<ffff000008d478b8>] acpi_processor_driver_init+0x2c/0xb0
>> [ 7.229996] [<ffff000008083168>] do_one_initcall+0x38/0x130
>> [ 7.230000] [<ffff000008d20d6c>] kernel_init_freeable+0x210/0x2b4
>> [ 7.230004] [<ffff000008945d90>] kernel_init+0x10/0x110
>> [ 7.230007] [<ffff000008082e80>] ret_from_fork+0x10/0x50
>>
>> It's because the spinlock inside pcc_mbox_request_channel() is
>> kept too long. This patch releases spinlock before request_irq()
>> and free_irq() to fix this issue as spinlock is only needed to
>> protect the channel data.
>>
>> Signed-off-by: Hoan Tran <[email protected]>
>> ---
>> v3
>> * Free mailbox irq before reset the channel data
>> * Free channel if it fails to request the mailbox irq
>>
>> v2
>> * Release spinlock before request_irq() and free_irq() instead of
>> using mutex
>>
>>
>> drivers/mailbox/pcc.c | 70 +++++++++++++++++++++++++--------------------------
>> 1 file changed, 35 insertions(+), 35 deletions(-)
>>
>> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
>> index 08c87fa..4b2f061 100644
>> --- a/drivers/mailbox/pcc.c
>> +++ b/drivers/mailbox/pcc.c
>> @@ -224,6 +224,38 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
>> }
>>
>> /**
>> + * pcc_mbox_free_channel - Clients call this to free their Channel.
>> + *
>> + * @chan: Pointer to the mailbox channel as returned by
>> + * pcc_mbox_request_channel()
>> + */
>> +void pcc_mbox_free_channel(struct mbox_chan *chan)
>> +{
>> + u32 id = chan - pcc_mbox_channels;
>> + unsigned long flags;
>> +
>> + if (!chan || !chan->cl)
>> + return;
>> +
>> + if (id >= pcc_mbox_ctrl.num_chans) {
>> + pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
>> + return;
>> + }
>> +
>> + if (pcc_doorbell_irq[id] > 0)
>> + devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
>> +
>> + spin_lock_irqsave(&chan->lock, flags);
>> + chan->cl = NULL;
>> + chan->active_req = NULL;
>> + if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
>> + chan->txdone_method = TXDONE_BY_POLL;
>> +
>> + spin_unlock_irqrestore(&chan->lock, flags);
>> +}
>> +EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
>> +
>> +/**
>> * pcc_mbox_request_channel - PCC clients call this function to
>> * request a pointer to their PCC subspace, from which they
>> * can get the details of communicating with the remote.
>> @@ -267,6 +299,8 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
>> if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
>> chan->txdone_method |= TXDONE_BY_ACK;
>>
>> + spin_unlock_irqrestore(&chan->lock, flags);
>> +
>> if (pcc_doorbell_irq[subspace_id] > 0) {
>> int rc;
>>
>> @@ -275,50 +309,16 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
>> if (unlikely(rc)) {
>> dev_err(dev, "failed to register PCC interrupt %d\n",
>> pcc_doorbell_irq[subspace_id]);
>> + pcc_mbox_free_channel(chan);
>> chan = ERR_PTR(rc);
>> }
>> }
>>
>> - spin_unlock_irqrestore(&chan->lock, flags);
>> -
>> return chan;
>> }
>> EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
>>
>> /**
>> - * pcc_mbox_free_channel - Clients call this to free their Channel.
>> - *
>> - * @chan: Pointer to the mailbox channel as returned by
>> - * pcc_mbox_request_channel()
>> - */
>> -void pcc_mbox_free_channel(struct mbox_chan *chan)
>> -{
>> - u32 id = chan - pcc_mbox_channels;
>> - unsigned long flags;
>> -
>> - if (!chan || !chan->cl)
>> - return;
>> -
>> - if (id >= pcc_mbox_ctrl.num_chans) {
>> - pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
>> - return;
>> - }
>> -
>> - spin_lock_irqsave(&chan->lock, flags);
>> - chan->cl = NULL;
>> - chan->active_req = NULL;
>> - if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
>> - chan->txdone_method = TXDONE_BY_POLL;
>> -
>> - if (pcc_doorbell_irq[id] > 0)
>> - devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
>> -
>> - spin_unlock_irqrestore(&chan->lock, flags);
>> -}
>> -EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
Instead of completely relocating an exported function within the file, I think
we can just include the "pcc.h" header, which makes it a little easier to review.
Otherwise, the control flow looks ok now.
--
Thanks,
Prashanth
Hi,
On Sun, Nov 13, 2016 at 11:44 AM, Prakash, Prashanth
<[email protected]> wrote:
> HI Hoan,
>
> On 11/9/2016 11:39 PM, Hoan Tran wrote:
>> Hi All,
>>
>> On Thu, Oct 27, 2016 at 3:34 PM, Hoan Tran <[email protected]> wrote:
>>> This patch fixes the lockdep warning below
>>>
>>> [ 7.229767] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
>>> [ 7.229776] ------------[ cut here ]------------
>>> [ 7.229787] WARNING: CPU: 1 PID: 1 at linux-next/kernel/locking/lockdep.c:2876 loc
>>> kdep_trace_alloc+0xe0/0xf0
>>> [ 7.229790] Modules linked in:
>>> [ 7.229793]
>>> [ 7.229798] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.8.0-11756-g86c5152 #46
>>> ...
>>> [ 7.229900] Call trace:
>>> [ 7.229903] Exception stack(0xffff8007da837890 to 0xffff8007da8379c0)
>>> [ 7.229906] 7880: ffff8007da834000 0001000000000000
>>> [ 7.229909] 78a0: ffff8007da837a70 ffff0000081111a0 00000000600000c5 000000000000003d
>>> [ 7.229912] 78c0: 9374bc6a7f3c7832 0000000000381878 ffff000009db7ab8 000000000000002f
>>> [ 7.229915] 78e0: ffff00000811aabc ffff000008be2548 ffff8007da837990 ffff00000811adf8
>>> [ 7.229918] 7900: ffff8007da834000 00000000024080c0 00000000000000c0 ffff000009021000
>>> [ 7.229921] 7920: 0000000000000000 0000000000000000 ffff000008c8f7c8 ffff8007da579810
>>> [ 7.229923] 7940: 000000000000002f ffff8007da858000 0000000000000000 0000000000000001
>>> [ 7.229926] 7960: 0000000000000001 0000000000000000 ffff00000811a468 0000000000000002
>>> [ 7.229929] 7980: 656c62617369645f 0000000000038187 00000000000000ee ffff8007da837850
>>> [ 7.229932] 79a0: ffff000009db50c0 ffff000009db569d 0000000000000006 ffff000089db568f
>>> [ 7.229936] [<ffff0000081111a0>] lockdep_trace_alloc+0xe0/0xf0
>>> [ 7.229940] [<ffff0000081f4950>] __kmalloc_track_caller+0x50/0x250
>>> [ 7.229945] [<ffff00000857c088>] devres_alloc_node+0x28/0x60
>>> [ 7.229949] [<ffff0000081220e0>] devm_request_threaded_irq+0x50/0xe0
>>> [ 7.229955] [<ffff0000087e6220>] pcc_mbox_request_channel+0x110/0x170
>>> [ 7.229960] [<ffff0000084b2660>] acpi_cppc_processor_probe+0x264/0x414
>>> [ 7.229963] [<ffff0000084ae9f4>] __acpi_processor_start+0x28/0xa0
>>> [ 7.229966] [<ffff0000084aeab0>] acpi_processor_start+0x44/0x54
>>> [ 7.229970] [<ffff00000857897c>] driver_probe_device+0x1fc/0x2b0
>>> [ 7.229974] [<ffff000008578ae4>] __driver_attach+0xb4/0xc0
>>> [ 7.229977] [<ffff00000857683c>] bus_for_each_dev+0x5c/0xa0
>>> [ 7.229980] [<ffff000008578110>] driver_attach+0x20/0x30
>>> [ 7.229983] [<ffff000008577c20>] bus_add_driver+0x110/0x230
>>> [ 7.229987] [<ffff000008579320>] driver_register+0x60/0x100
>>> [ 7.229991] [<ffff000008d478b8>] acpi_processor_driver_init+0x2c/0xb0
>>> [ 7.229996] [<ffff000008083168>] do_one_initcall+0x38/0x130
>>> [ 7.230000] [<ffff000008d20d6c>] kernel_init_freeable+0x210/0x2b4
>>> [ 7.230004] [<ffff000008945d90>] kernel_init+0x10/0x110
>>> [ 7.230007] [<ffff000008082e80>] ret_from_fork+0x10/0x50
>>>
>>> It's because the spinlock inside pcc_mbox_request_channel() is
>>> kept too long. This patch releases spinlock before request_irq()
>>> and free_irq() to fix this issue as spinlock is only needed to
>>> protect the channel data.
>>>
>>> Signed-off-by: Hoan Tran <[email protected]>
>>> ---
>>> v3
>>> * Free mailbox irq before reset the channel data
>>> * Free channel if it fails to request the mailbox irq
>>>
>>> v2
>>> * Release spinlock before request_irq() and free_irq() instead of
>>> using mutex
>>>
>>>
>>> drivers/mailbox/pcc.c | 70 +++++++++++++++++++++++++--------------------------
>>> 1 file changed, 35 insertions(+), 35 deletions(-)
>>>
>>> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
>>> index 08c87fa..4b2f061 100644
>>> --- a/drivers/mailbox/pcc.c
>>> +++ b/drivers/mailbox/pcc.c
>>> @@ -224,6 +224,38 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
>>> }
>>>
>>> /**
>>> + * pcc_mbox_free_channel - Clients call this to free their Channel.
>>> + *
>>> + * @chan: Pointer to the mailbox channel as returned by
>>> + * pcc_mbox_request_channel()
>>> + */
>>> +void pcc_mbox_free_channel(struct mbox_chan *chan)
>>> +{
>>> + u32 id = chan - pcc_mbox_channels;
>>> + unsigned long flags;
>>> +
>>> + if (!chan || !chan->cl)
>>> + return;
>>> +
>>> + if (id >= pcc_mbox_ctrl.num_chans) {
>>> + pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
>>> + return;
>>> + }
>>> +
>>> + if (pcc_doorbell_irq[id] > 0)
>>> + devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
>>> +
>>> + spin_lock_irqsave(&chan->lock, flags);
>>> + chan->cl = NULL;
>>> + chan->active_req = NULL;
>>> + if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
>>> + chan->txdone_method = TXDONE_BY_POLL;
>>> +
>>> + spin_unlock_irqrestore(&chan->lock, flags);
>>> +}
>>> +EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
>>> +
>>> +/**
>>> * pcc_mbox_request_channel - PCC clients call this function to
>>> * request a pointer to their PCC subspace, from which they
>>> * can get the details of communicating with the remote.
>>> @@ -267,6 +299,8 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
>>> if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
>>> chan->txdone_method |= TXDONE_BY_ACK;
>>>
>>> + spin_unlock_irqrestore(&chan->lock, flags);
>>> +
>>> if (pcc_doorbell_irq[subspace_id] > 0) {
>>> int rc;
>>>
>>> @@ -275,50 +309,16 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
>>> if (unlikely(rc)) {
>>> dev_err(dev, "failed to register PCC interrupt %d\n",
>>> pcc_doorbell_irq[subspace_id]);
>>> + pcc_mbox_free_channel(chan);
>>> chan = ERR_PTR(rc);
>>> }
>>> }
>>>
>>> - spin_unlock_irqrestore(&chan->lock, flags);
>>> -
>>> return chan;
>>> }
>>> EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
>>>
>>> /**
>>> - * pcc_mbox_free_channel - Clients call this to free their Channel.
>>> - *
>>> - * @chan: Pointer to the mailbox channel as returned by
>>> - * pcc_mbox_request_channel()
>>> - */
>>> -void pcc_mbox_free_channel(struct mbox_chan *chan)
>>> -{
>>> - u32 id = chan - pcc_mbox_channels;
>>> - unsigned long flags;
>>> -
>>> - if (!chan || !chan->cl)
>>> - return;
>>> -
>>> - if (id >= pcc_mbox_ctrl.num_chans) {
>>> - pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
>>> - return;
>>> - }
>>> -
>>> - spin_lock_irqsave(&chan->lock, flags);
>>> - chan->cl = NULL;
>>> - chan->active_req = NULL;
>>> - if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
>>> - chan->txdone_method = TXDONE_BY_POLL;
>>> -
>>> - if (pcc_doorbell_irq[id] > 0)
>>> - devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
>>> -
>>> - spin_unlock_irqrestore(&chan->lock, flags);
>>> -}
>>> -EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
> Instead of completely relocating an exported function within the file, I think
> we can just include the "pcc.h" header, which makes it a little easier to review.
I just sent out another patch which included pcc.h instead.
Thanks
Hoan
>
> Otherwise, the control flow looks ok now.
>
> --
> Thanks,
> Prashanth