diff mbox

[V2] mmc: sdhci: don't read cd-gpio while holding spinlock

Message ID 1395625380-12507-1-git-send-email-abrestic@chromium.org (mailing list archive)
State New, archived
Headers show

Commit Message

Andrew Bresticker March 24, 2014, 1:43 a.m. UTC 
sdhci_request() and sdhci_card_event() read the cd-gpio via
mmc_gpio_get_cd(), which can sleep, while holding host->lock.
This may result in the following BUG:

  BUG: spinlock wrong CPU on CPU#2, kworker/u8:16/4296
  lock: 0xea6b9c80, .magic: dead4ead, .owner: kworker/u8:16/4296, .owner_cpu: 0
  CPU: 2 PID: 4296 Comm: kworker/u8:16 Tainted: G         C   3.10.18 #137
  Workqueue: kmmcd mmc_rescan
  [<8020cf8c>] (unwind_backtrace+0x0/0x118) from [<8020a0c8>] (show_stack+0x20/0x24)
  [<8020a0c8>] (show_stack+0x20/0x24) from [<8075e5b8>] (dump_stack+0x20/0x28)
  [<8075e5b8>] (dump_stack+0x20/0x28) from [<804184a8>] (spin_dump+0x80/0x94)
  [<804184a8>] (spin_dump+0x80/0x94) from [<804184e8>] (spin_bug+0x2c/0x30)
  [<804184e8>] (spin_bug+0x2c/0x30) from [<80418790>] (do_raw_spin_unlock+0x94/0xd4)
  [<80418790>] (do_raw_spin_unlock+0x94/0xd4) from [<80761a44>] (_raw_spin_unlock_irqrestore+0x1c/0x24)
  [<80761a44>] (_raw_spin_unlock_irqrestore+0x1c/0x24) from [<805ff66c>] (sdhci_request+0x1c8/0x1d0)
  [<805ff66c>] (sdhci_request+0x1c8/0x1d0) from [<805ebb5c>] (mmc_start_request+0xec/0xf4)
  [<805ebb5c>] (mmc_start_request+0xec/0xf4) from [<805ebcbc>] (mmc_wait_for_req+0x80/0xf4)
  ...

Read the cd-gpio before acquiring the spinlock instead.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
---
 drivers/mmc/host/sdhci.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Comments

Adrian Hunter March 24, 2014, 6:19 a.m. UTC | #1 
On 24.03.2014 03:43, Andrew Bresticker wrote:
> sdhci_request() and sdhci_card_event() read the cd-gpio via
> mmc_gpio_get_cd(), which can sleep, while holding host->lock.
> This may result in the following BUG:
> 
>   BUG: spinlock wrong CPU on CPU#2, kworker/u8:16/4296
>   lock: 0xea6b9c80, .magic: dead4ead, .owner: kworker/u8:16/4296, .owner_cpu: 0
>   CPU: 2 PID: 4296 Comm: kworker/u8:16 Tainted: G         C   3.10.18 #137
>   Workqueue: kmmcd mmc_rescan
>   [<8020cf8c>] (unwind_backtrace+0x0/0x118) from [<8020a0c8>] (show_stack+0x20/0x24)
>   [<8020a0c8>] (show_stack+0x20/0x24) from [<8075e5b8>] (dump_stack+0x20/0x28)
>   [<8075e5b8>] (dump_stack+0x20/0x28) from [<804184a8>] (spin_dump+0x80/0x94)
>   [<804184a8>] (spin_dump+0x80/0x94) from [<804184e8>] (spin_bug+0x2c/0x30)
>   [<804184e8>] (spin_bug+0x2c/0x30) from [<80418790>] (do_raw_spin_unlock+0x94/0xd4)
>   [<80418790>] (do_raw_spin_unlock+0x94/0xd4) from [<80761a44>] (_raw_spin_unlock_irqrestore+0x1c/0x24)
>   [<80761a44>] (_raw_spin_unlock_irqrestore+0x1c/0x24) from [<805ff66c>] (sdhci_request+0x1c8/0x1d0)
>   [<805ff66c>] (sdhci_request+0x1c8/0x1d0) from [<805ebb5c>] (mmc_start_request+0xec/0xf4)
>   [<805ebb5c>] (mmc_start_request+0xec/0xf4) from [<805ebcbc>] (mmc_wait_for_req+0x80/0xf4)
>   ...
> 
> Read the cd-gpio before acquiring the spinlock instead.
> 
> Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
> ---
>  drivers/mmc/host/sdhci.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 04a5e25..328b250 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1340,6 +1340,7 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
>  	u32 tuning_opcode;
>  
>  	host = mmc_priv(mmc);
> +	present = mmc_gpio_get_cd(host->mmc);
>  
>  	sdhci_runtime_pm_get(host);
>  
> @@ -1371,7 +1372,6 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
>  	 *     zero: cd-gpio is used, and card is removed
>  	 *     one: cd-gpio is used, and card is present
>  	 */
> -	present = mmc_gpio_get_cd(host->mmc);
>  	if (present < 0) {
>  		/* If polling, assume that the card is always present. */
>  		if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION)
> @@ -2082,15 +2082,16 @@ static void sdhci_card_event(struct mmc_host *mmc)
>  {
>  	struct sdhci_host *host = mmc_priv(mmc);
>  	unsigned long flags;
> +	int present;
>  
>  	/* First check if client has provided their own card event */
>  	if (host->ops->card_event)
>  		host->ops->card_event(host);
>  
> +	present = sdhci_get_cd(mmc);

Shouldn't that be sdhci_do_get_cd(mmc) ?

>  	spin_lock_irqsave(&host->lock, flags);
>  
> -	/* Check host->mrq first in case we are runtime suspended */
> -	if (host->mrq && !sdhci_do_get_cd(host)) {
> +	if (host->mrq && !present) {
>  		pr_err("%s: Card removed during transfer!\n",
>  			mmc_hostname(host->mmc));
>  		pr_err("%s: Resetting controller.\n",
> 

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Andrew Bresticker March 24, 2014, 4:18 p.m. UTC | #2 
On Sun, Mar 23, 2014 at 11:19 PM, Adrian Hunter <adrian.hunter@intel.com> wrote:
> On 24.03.2014 03:43, Andrew Bresticker wrote:
>> sdhci_request() and sdhci_card_event() read the cd-gpio via
>> mmc_gpio_get_cd(), which can sleep, while holding host->lock.
>> This may result in the following BUG:
>>
>>   BUG: spinlock wrong CPU on CPU#2, kworker/u8:16/4296
>>   lock: 0xea6b9c80, .magic: dead4ead, .owner: kworker/u8:16/4296, .owner_cpu: 0
>>   CPU: 2 PID: 4296 Comm: kworker/u8:16 Tainted: G         C   3.10.18 #137
>>   Workqueue: kmmcd mmc_rescan
>>   [<8020cf8c>] (unwind_backtrace+0x0/0x118) from [<8020a0c8>] (show_stack+0x20/0x24)
>>   [<8020a0c8>] (show_stack+0x20/0x24) from [<8075e5b8>] (dump_stack+0x20/0x28)
>>   [<8075e5b8>] (dump_stack+0x20/0x28) from [<804184a8>] (spin_dump+0x80/0x94)
>>   [<804184a8>] (spin_dump+0x80/0x94) from [<804184e8>] (spin_bug+0x2c/0x30)
>>   [<804184e8>] (spin_bug+0x2c/0x30) from [<80418790>] (do_raw_spin_unlock+0x94/0xd4)
>>   [<80418790>] (do_raw_spin_unlock+0x94/0xd4) from [<80761a44>] (_raw_spin_unlock_irqrestore+0x1c/0x24)
>>   [<80761a44>] (_raw_spin_unlock_irqrestore+0x1c/0x24) from [<805ff66c>] (sdhci_request+0x1c8/0x1d0)
>>   [<805ff66c>] (sdhci_request+0x1c8/0x1d0) from [<805ebb5c>] (mmc_start_request+0xec/0xf4)
>>   [<805ebb5c>] (mmc_start_request+0xec/0xf4) from [<805ebcbc>] (mmc_wait_for_req+0x80/0xf4)
>>   ...
>>
>> Read the cd-gpio before acquiring the spinlock instead.
>>
>> Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
>> ---
>>  drivers/mmc/host/sdhci.c | 7 ++++---
>>  1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index 04a5e25..328b250 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -1340,6 +1340,7 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
>>       u32 tuning_opcode;
>>
>>       host = mmc_priv(mmc);
>> +     present = mmc_gpio_get_cd(host->mmc);
>>
>>       sdhci_runtime_pm_get(host);
>>
>> @@ -1371,7 +1372,6 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
>>        *     zero: cd-gpio is used, and card is removed
>>        *     one: cd-gpio is used, and card is present
>>        */
>> -     present = mmc_gpio_get_cd(host->mmc);
>>       if (present < 0) {
>>               /* If polling, assume that the card is always present. */
>>               if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION)
>> @@ -2082,15 +2082,16 @@ static void sdhci_card_event(struct mmc_host *mmc)
>>  {
>>       struct sdhci_host *host = mmc_priv(mmc);
>>       unsigned long flags;
>> +     int present;
>>
>>       /* First check if client has provided their own card event */
>>       if (host->ops->card_event)
>>               host->ops->card_event(host);
>>
>> +     present = sdhci_get_cd(mmc);
>
> Shouldn't that be sdhci_do_get_cd(mmc) ?

No I do mean shdic_get_cd().  We might be runtime suspended so we need
sdhci_get_cd() to increment the device usage count and do a runtime
resume if necessary.

>
>>       spin_lock_irqsave(&host->lock, flags);
>>
>> -     /* Check host->mrq first in case we are runtime suspended */
>> -     if (host->mrq && !sdhci_do_get_cd(host)) {
>> +     if (host->mrq && !present) {
>>               pr_err("%s: Card removed during transfer!\n",
>>                       mmc_hostname(host->mmc));
>>               pr_err("%s: Resetting controller.\n",
>>
>
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Adrian Hunter March 25, 2014, 8:25 a.m. UTC | #3 
On 24.03.2014 18:18, Andrew Bresticker wrote:
> On Sun, Mar 23, 2014 at 11:19 PM, Adrian Hunter <adrian.hunter@intel.com> wrote:
>> On 24.03.2014 03:43, Andrew Bresticker wrote:
>>> sdhci_request() and sdhci_card_event() read the cd-gpio via
>>> mmc_gpio_get_cd(), which can sleep, while holding host->lock.
>>> This may result in the following BUG:
>>>
>>>   BUG: spinlock wrong CPU on CPU#2, kworker/u8:16/4296
>>>   lock: 0xea6b9c80, .magic: dead4ead, .owner: kworker/u8:16/4296, .owner_cpu: 0
>>>   CPU: 2 PID: 4296 Comm: kworker/u8:16 Tainted: G         C   3.10.18 #137
>>>   Workqueue: kmmcd mmc_rescan
>>>   [<8020cf8c>] (unwind_backtrace+0x0/0x118) from [<8020a0c8>] (show_stack+0x20/0x24)
>>>   [<8020a0c8>] (show_stack+0x20/0x24) from [<8075e5b8>] (dump_stack+0x20/0x28)
>>>   [<8075e5b8>] (dump_stack+0x20/0x28) from [<804184a8>] (spin_dump+0x80/0x94)
>>>   [<804184a8>] (spin_dump+0x80/0x94) from [<804184e8>] (spin_bug+0x2c/0x30)
>>>   [<804184e8>] (spin_bug+0x2c/0x30) from [<80418790>] (do_raw_spin_unlock+0x94/0xd4)
>>>   [<80418790>] (do_raw_spin_unlock+0x94/0xd4) from [<80761a44>] (_raw_spin_unlock_irqrestore+0x1c/0x24)
>>>   [<80761a44>] (_raw_spin_unlock_irqrestore+0x1c/0x24) from [<805ff66c>] (sdhci_request+0x1c8/0x1d0)
>>>   [<805ff66c>] (sdhci_request+0x1c8/0x1d0) from [<805ebb5c>] (mmc_start_request+0xec/0xf4)
>>>   [<805ebb5c>] (mmc_start_request+0xec/0xf4) from [<805ebcbc>] (mmc_wait_for_req+0x80/0xf4)
>>>   ...
>>>
>>> Read the cd-gpio before acquiring the spinlock instead.
>>>
>>> Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
>>> ---
>>>  drivers/mmc/host/sdhci.c | 7 ++++---
>>>  1 file changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> index 04a5e25..328b250 100644
>>> --- a/drivers/mmc/host/sdhci.c
>>> +++ b/drivers/mmc/host/sdhci.c
>>> @@ -1340,6 +1340,7 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
>>>       u32 tuning_opcode;
>>>
>>>       host = mmc_priv(mmc);
>>> +     present = mmc_gpio_get_cd(host->mmc);
>>>
>>>       sdhci_runtime_pm_get(host);
>>>
>>> @@ -1371,7 +1372,6 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
>>>        *     zero: cd-gpio is used, and card is removed
>>>        *     one: cd-gpio is used, and card is present
>>>        */
>>> -     present = mmc_gpio_get_cd(host->mmc);
>>>       if (present < 0) {
>>>               /* If polling, assume that the card is always present. */
>>>               if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION)
>>> @@ -2082,15 +2082,16 @@ static void sdhci_card_event(struct mmc_host *mmc)
>>>  {
>>>       struct sdhci_host *host = mmc_priv(mmc);
>>>       unsigned long flags;
>>> +     int present;
>>>
>>>       /* First check if client has provided their own card event */
>>>       if (host->ops->card_event)
>>>               host->ops->card_event(host);
>>>
>>> +     present = sdhci_get_cd(mmc);
>>
>> Shouldn't that be sdhci_do_get_cd(mmc) ?
> 
> No I do mean shdic_get_cd().  We might be runtime suspended so we need
> sdhci_get_cd() to increment the device usage count and do a runtime
> resume if necessary.

Very true.

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> 
>>
>>>       spin_lock_irqsave(&host->lock, flags);
>>>
>>> -     /* Check host->mrq first in case we are runtime suspended */
>>> -     if (host->mrq && !sdhci_do_get_cd(host)) {
>>> +     if (host->mrq && !present) {
>>>               pr_err("%s: Card removed during transfer!\n",
>>>                       mmc_hostname(host->mmc));
>>>               pr_err("%s: Resetting controller.\n",
>>>
>>
> 
> 

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diff mbox

Patch

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 04a5e25..328b250 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1340,6 +1340,7 @@  static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 	u32 tuning_opcode;
 
 	host = mmc_priv(mmc);
+	present = mmc_gpio_get_cd(host->mmc);
 
 	sdhci_runtime_pm_get(host);
 
@@ -1371,7 +1372,6 @@  static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 	 *     zero: cd-gpio is used, and card is removed
 	 *     one: cd-gpio is used, and card is present
 	 */
-	present = mmc_gpio_get_cd(host->mmc);
 	if (present < 0) {
 		/* If polling, assume that the card is always present. */
 		if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION)
@@ -2082,15 +2082,16 @@  static void sdhci_card_event(struct mmc_host *mmc)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
 	unsigned long flags;
+	int present;
 
 	/* First check if client has provided their own card event */
 	if (host->ops->card_event)
 		host->ops->card_event(host);
 
+	present = sdhci_get_cd(mmc);
 	spin_lock_irqsave(&host->lock, flags);
 
-	/* Check host->mrq first in case we are runtime suspended */
-	if (host->mrq && !sdhci_do_get_cd(host)) {
+	if (host->mrq && !present) {
 		pr_err("%s: Card removed during transfer!\n",
 			mmc_hostname(host->mmc));
 		pr_err("%s: Resetting controller.\n",