2014-01-17 20:04:23

by Andrew Bresticker

[permalink] [raw]
Subject: [PATCH] mmc: sdhci: fix possible scheduling while atomic

sdhci_execute_tuning() takes host->lock without disabling interrupts.
Use spin_lock_irq{save,restore} instead so that we avoid taking an
interrupt and scheduling while holding host->lock.

Signed-off-by: Andrew Bresticker <[email protected]>
---
drivers/mmc/host/sdhci.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index ec3eb30..84c80e7 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1857,12 +1857,13 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
unsigned long timeout;
int err = 0;
bool requires_tuning_nonuhs = false;
+ unsigned long flags;

host = mmc_priv(mmc);

sdhci_runtime_pm_get(host);
disable_irq(host->irq);
- spin_lock(&host->lock);
+ spin_lock_irqsave(&host->lock, flags);

ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);

@@ -1882,14 +1883,14 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
requires_tuning_nonuhs)
ctrl |= SDHCI_CTRL_EXEC_TUNING;
else {
- spin_unlock(&host->lock);
+ spin_unlock_irqrestore(&host->lock, flags);
enable_irq(host->irq);
sdhci_runtime_pm_put(host);
return 0;
}

if (host->ops->platform_execute_tuning) {
- spin_unlock(&host->lock);
+ spin_unlock_irqrestore(&host->lock, flags);
enable_irq(host->irq);
err = host->ops->platform_execute_tuning(host, opcode);
sdhci_runtime_pm_put(host);
@@ -1963,7 +1964,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
host->cmd = NULL;
host->mrq = NULL;

- spin_unlock(&host->lock);
+ spin_unlock_irqrestore(&host->lock, flags);
enable_irq(host->irq);

/* Wait for Buffer Read Ready interrupt */
@@ -1971,7 +1972,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
(host->tuning_done == 1),
msecs_to_jiffies(50));
disable_irq(host->irq);
- spin_lock(&host->lock);
+ spin_lock_irqsave(&host->lock, flags);

if (!host->tuning_done) {
pr_info(DRIVER_NAME ": Timeout waiting for "
@@ -2046,7 +2047,7 @@ out:
err = 0;

sdhci_clear_set_irqs(host, SDHCI_INT_DATA_AVAIL, ier);
- spin_unlock(&host->lock);
+ spin_unlock_irqrestore(&host->lock, flags);
enable_irq(host->irq);
sdhci_runtime_pm_put(host);

--
1.8.5.2


2014-01-17 22:59:05

by Philip Rakity

[permalink] [raw]
Subject: Re: [PATCH] mmc: sdhci: fix possible scheduling while atomic


On Jan 17, 2014, at 7:57 PM, Andrew Bresticker <[email protected]> wrote:

> sdhci_execute_tuning() takes host->lock without disabling interrupts.
> Use spin_lock_irq{save,restore} instead so that we avoid taking an
> interrupt and scheduling while holding host->lock.
>
> Signed-off-by: Andrew Bresticker <[email protected]>
> ---
> drivers/mmc/host/sdhci.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index ec3eb30..84c80e7 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1857,12 +1857,13 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
> unsigned long timeout;
> int err = 0;
> bool requires_tuning_nonuhs = false;
> + unsigned long flags;
>
> host = mmc_priv(mmc);
>
> sdhci_runtime_pm_get(host);
> disable_irq(host->irq);
> - spin_lock(&host->lock);
> + spin_lock_irqsave(&host->lock, flags);


The disable_irq() call stops the controller from doing interrupts.
Please explain what problem you are seeing

>
> ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>
> @@ -1882,14 +1883,14 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
> requires_tuning_nonuhs)
> ctrl |= SDHCI_CTRL_EXEC_TUNING;
> else {
> - spin_unlock(&host->lock);
> + spin_unlock_irqrestore(&host->lock, flags);
> enable_irq(host->irq);
> sdhci_runtime_pm_put(host);
> return 0;
> }
>
> if (host->ops->platform_execute_tuning) {
> - spin_unlock(&host->lock);
> + spin_unlock_irqrestore(&host->lock, flags);
> enable_irq(host->irq);
> err = host->ops->platform_execute_tuning(host, opcode);
> sdhci_runtime_pm_put(host);
> @@ -1963,7 +1964,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
> host->cmd = NULL;
> host->mrq = NULL;
>
> - spin_unlock(&host->lock);
> + spin_unlock_irqrestore(&host->lock, flags);
> enable_irq(host->irq);
>
> /* Wait for Buffer Read Ready interrupt */
> @@ -1971,7 +1972,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
> (host->tuning_done == 1),
> msecs_to_jiffies(50));
> disable_irq(host->irq);
> - spin_lock(&host->lock);
> + spin_lock_irqsave(&host->lock, flags);
>
> if (!host->tuning_done) {
> pr_info(DRIVER_NAME ": Timeout waiting for "
> @@ -2046,7 +2047,7 @@ out:
> err = 0;
>
> sdhci_clear_set_irqs(host, SDHCI_INT_DATA_AVAIL, ier);
> - spin_unlock(&host->lock);
> + spin_unlock_irqrestore(&host->lock, flags);
> enable_irq(host->irq);
> sdhci_runtime_pm_put(host);
>
> --
> 1.8.5.2
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html

2014-01-17 23:10:27

by Andrew Bresticker

[permalink] [raw]
Subject: Re: [PATCH] mmc: sdhci: fix possible scheduling while atomic

On Fri, Jan 17, 2014 at 2:58 PM, Philip Rakity <[email protected]> wrote:
>
> On Jan 17, 2014, at 7:57 PM, Andrew Bresticker <[email protected]> wrote:
>
>> sdhci_execute_tuning() takes host->lock without disabling interrupts.
>> Use spin_lock_irq{save,restore} instead so that we avoid taking an
>> interrupt and scheduling while holding host->lock.
>>
>> Signed-off-by: Andrew Bresticker <[email protected]>
>> ---
>> drivers/mmc/host/sdhci.c | 13 +++++++------
>> 1 file changed, 7 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index ec3eb30..84c80e7 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -1857,12 +1857,13 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> unsigned long timeout;
>> int err = 0;
>> bool requires_tuning_nonuhs = false;
>> + unsigned long flags;
>>
>> host = mmc_priv(mmc);
>>
>> sdhci_runtime_pm_get(host);
>> disable_irq(host->irq);
>> - spin_lock(&host->lock);
>> + spin_lock_irqsave(&host->lock, flags);
>
>
> The disable_irq() call stops the controller from doing interrupts.

Right, but it does not disable other IRQ sources that could cause us
to schedule.

> Please explain what problem you are seeing

The issue we were seeing was that a card-detect interrupt was
triggered (*not* the controller interrupt), causing the card-detect
irq thread to recurse on host->lock:

[ 60.962218] BUG: spinlock cpu recursion on CPU#0, irq/362-700b040/89
[ 60.975253] lock: 0xee210c80, .magic: dead4ead, .owner:
kworker/u8:1/33, .owner_cpu: 0
[ 60.991638] CPU: 0 PID: 89 Comm: irq/362-700b040 Not tainted 3.10.18 #2
[ 61.005199] [<800153cc>] (unwind_backtrace+0x0/0x118) from
[<800124e4>] (show_stack+0x20/0x24)
[ 61.022824] [<800124e4>] (show_stack+0x20/0x24) from [<8053d584>]
(dump_stack+0x20/0x28)
[ 61.039389] [<8053d584>] (dump_stack+0x20/0x28) from [<8021d508>]
(spin_dump+0x80/0x94)
[ 61.055773] [<8021d508>] (spin_dump+0x80/0x94) from [<8021d548>]
(spin_bug+0x2c/0x30)
[ 61.071803] [<8021d548>] (spin_bug+0x2c/0x30) from [<8021d61c>]
(do_raw_spin_lock+0x70/0x15c)
[ 61.089250] [<8021d61c>] (do_raw_spin_lock+0x70/0x15c) from
[<8054098c>] (_raw_spin_lock_irqsave+0x20/0x28)
[ 61.109175] [<8054098c>] (_raw_spin_lock_irqsave+0x20/0x28) from
[<803e2af0>] (sdhci_card_event+0x28/0xfc)
[ 61.128922] [<803e2af0>] (sdhci_card_event+0x28/0xfc) from
[<803dc880>] (mmc_gpio_cd_irqt+0x30/0x4c)
[ 61.147609] [<803dc880>] (mmc_gpio_cd_irqt+0x30/0x4c) from
[<80091858>] (irq_thread+0xf0/0x224)
[ 61.165412] [<80091858>] (irq_thread+0xf0/0x224) from [<80050db4>]
(kthread+0xc8/0xd8)
[ 61.181623] [<80050db4>] (kthread+0xc8/0xd8) from [<8000e4d8>]
(ret_from_fork+0x14/0x20)

Thanks,
Andrew

>
>>
>> ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>>
>> @@ -1882,14 +1883,14 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> requires_tuning_nonuhs)
>> ctrl |= SDHCI_CTRL_EXEC_TUNING;
>> else {
>> - spin_unlock(&host->lock);
>> + spin_unlock_irqrestore(&host->lock, flags);
>> enable_irq(host->irq);
>> sdhci_runtime_pm_put(host);
>> return 0;
>> }
>>
>> if (host->ops->platform_execute_tuning) {
>> - spin_unlock(&host->lock);
>> + spin_unlock_irqrestore(&host->lock, flags);
>> enable_irq(host->irq);
>> err = host->ops->platform_execute_tuning(host, opcode);
>> sdhci_runtime_pm_put(host);
>> @@ -1963,7 +1964,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> host->cmd = NULL;
>> host->mrq = NULL;
>>
>> - spin_unlock(&host->lock);
>> + spin_unlock_irqrestore(&host->lock, flags);
>> enable_irq(host->irq);
>>
>> /* Wait for Buffer Read Ready interrupt */
>> @@ -1971,7 +1972,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> (host->tuning_done == 1),
>> msecs_to_jiffies(50));
>> disable_irq(host->irq);
>> - spin_lock(&host->lock);
>> + spin_lock_irqsave(&host->lock, flags);
>>
>> if (!host->tuning_done) {
>> pr_info(DRIVER_NAME ": Timeout waiting for "
>> @@ -2046,7 +2047,7 @@ out:
>> err = 0;
>>
>> sdhci_clear_set_irqs(host, SDHCI_INT_DATA_AVAIL, ier);
>> - spin_unlock(&host->lock);
>> + spin_unlock_irqrestore(&host->lock, flags);
>> enable_irq(host->irq);
>> sdhci_runtime_pm_put(host);
>>
>> --
>> 1.8.5.2
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>> the body of a message to [email protected]
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>

2014-01-17 23:12:06

by John Tobias

[permalink] [raw]
Subject: Re: [PATCH] mmc: sdhci: fix possible scheduling while atomic

There's an existing patch for that...
http://www.spinics.net/lists/arm-kernel/msg296596.html

On Fri, Jan 17, 2014 at 2:58 PM, Philip Rakity <[email protected]> wrote:
>
> On Jan 17, 2014, at 7:57 PM, Andrew Bresticker <[email protected]> wrote:
>
>> sdhci_execute_tuning() takes host->lock without disabling interrupts.
>> Use spin_lock_irq{save,restore} instead so that we avoid taking an
>> interrupt and scheduling while holding host->lock.
>>
>> Signed-off-by: Andrew Bresticker <[email protected]>
>> ---
>> drivers/mmc/host/sdhci.c | 13 +++++++------
>> 1 file changed, 7 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index ec3eb30..84c80e7 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -1857,12 +1857,13 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> unsigned long timeout;
>> int err = 0;
>> bool requires_tuning_nonuhs = false;
>> + unsigned long flags;
>>
>> host = mmc_priv(mmc);
>>
>> sdhci_runtime_pm_get(host);
>> disable_irq(host->irq);
>> - spin_lock(&host->lock);
>> + spin_lock_irqsave(&host->lock, flags);
>
>
> The disable_irq() call stops the controller from doing interrupts.
> Please explain what problem you are seeing
>
>>
>> ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>>
>> @@ -1882,14 +1883,14 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> requires_tuning_nonuhs)
>> ctrl |= SDHCI_CTRL_EXEC_TUNING;
>> else {
>> - spin_unlock(&host->lock);
>> + spin_unlock_irqrestore(&host->lock, flags);
>> enable_irq(host->irq);
>> sdhci_runtime_pm_put(host);
>> return 0;
>> }
>>
>> if (host->ops->platform_execute_tuning) {
>> - spin_unlock(&host->lock);
>> + spin_unlock_irqrestore(&host->lock, flags);
>> enable_irq(host->irq);
>> err = host->ops->platform_execute_tuning(host, opcode);
>> sdhci_runtime_pm_put(host);
>> @@ -1963,7 +1964,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> host->cmd = NULL;
>> host->mrq = NULL;
>>
>> - spin_unlock(&host->lock);
>> + spin_unlock_irqrestore(&host->lock, flags);
>> enable_irq(host->irq);
>>
>> /* Wait for Buffer Read Ready interrupt */
>> @@ -1971,7 +1972,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>> (host->tuning_done == 1),
>> msecs_to_jiffies(50));
>> disable_irq(host->irq);
>> - spin_lock(&host->lock);
>> + spin_lock_irqsave(&host->lock, flags);
>>
>> if (!host->tuning_done) {
>> pr_info(DRIVER_NAME ": Timeout waiting for "
>> @@ -2046,7 +2047,7 @@ out:
>> err = 0;
>>
>> sdhci_clear_set_irqs(host, SDHCI_INT_DATA_AVAIL, ier);
>> - spin_unlock(&host->lock);
>> + spin_unlock_irqrestore(&host->lock, flags);
>> enable_irq(host->irq);
>> sdhci_runtime_pm_put(host);
>>
>> --
>> 1.8.5.2
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>> the body of a message to [email protected]
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
> --
> 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/

2014-01-17 23:16:45

by Andrew Bresticker

[permalink] [raw]
Subject: Re: [PATCH] mmc: sdhci: fix possible scheduling while atomic

On Fri, Jan 17, 2014 at 3:11 PM, John Tobias <[email protected]> wrote:
> There's an existing patch for that...
> http://www.spinics.net/lists/arm-kernel/msg296596.html

Ah, I see. Looks like it has yet to be picked up...

>
> On Fri, Jan 17, 2014 at 2:58 PM, Philip Rakity <[email protected]> wrote:
>>
>> On Jan 17, 2014, at 7:57 PM, Andrew Bresticker <[email protected]> wrote:
>>
>>> sdhci_execute_tuning() takes host->lock without disabling interrupts.
>>> Use spin_lock_irq{save,restore} instead so that we avoid taking an
>>> interrupt and scheduling while holding host->lock.
>>>
>>> Signed-off-by: Andrew Bresticker <[email protected]>
>>> ---
>>> drivers/mmc/host/sdhci.c | 13 +++++++------
>>> 1 file changed, 7 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> index ec3eb30..84c80e7 100644
>>> --- a/drivers/mmc/host/sdhci.c
>>> +++ b/drivers/mmc/host/sdhci.c
>>> @@ -1857,12 +1857,13 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>>> unsigned long timeout;
>>> int err = 0;
>>> bool requires_tuning_nonuhs = false;
>>> + unsigned long flags;
>>>
>>> host = mmc_priv(mmc);
>>>
>>> sdhci_runtime_pm_get(host);
>>> disable_irq(host->irq);
>>> - spin_lock(&host->lock);
>>> + spin_lock_irqsave(&host->lock, flags);
>>
>>
>> The disable_irq() call stops the controller from doing interrupts.
>> Please explain what problem you are seeing
>>
>>>
>>> ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>>>
>>> @@ -1882,14 +1883,14 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>>> requires_tuning_nonuhs)
>>> ctrl |= SDHCI_CTRL_EXEC_TUNING;
>>> else {
>>> - spin_unlock(&host->lock);
>>> + spin_unlock_irqrestore(&host->lock, flags);
>>> enable_irq(host->irq);
>>> sdhci_runtime_pm_put(host);
>>> return 0;
>>> }
>>>
>>> if (host->ops->platform_execute_tuning) {
>>> - spin_unlock(&host->lock);
>>> + spin_unlock_irqrestore(&host->lock, flags);
>>> enable_irq(host->irq);
>>> err = host->ops->platform_execute_tuning(host, opcode);
>>> sdhci_runtime_pm_put(host);
>>> @@ -1963,7 +1964,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>>> host->cmd = NULL;
>>> host->mrq = NULL;
>>>
>>> - spin_unlock(&host->lock);
>>> + spin_unlock_irqrestore(&host->lock, flags);
>>> enable_irq(host->irq);
>>>
>>> /* Wait for Buffer Read Ready interrupt */
>>> @@ -1971,7 +1972,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>>> (host->tuning_done == 1),
>>> msecs_to_jiffies(50));
>>> disable_irq(host->irq);
>>> - spin_lock(&host->lock);
>>> + spin_lock_irqsave(&host->lock, flags);
>>>
>>> if (!host->tuning_done) {
>>> pr_info(DRIVER_NAME ": Timeout waiting for "
>>> @@ -2046,7 +2047,7 @@ out:
>>> err = 0;
>>>
>>> sdhci_clear_set_irqs(host, SDHCI_INT_DATA_AVAIL, ier);
>>> - spin_unlock(&host->lock);
>>> + spin_unlock_irqrestore(&host->lock, flags);
>>> enable_irq(host->irq);
>>> sdhci_runtime_pm_put(host);
>>>
>>> --
>>> 1.8.5.2
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>>> the body of a message to [email protected]
>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
>> --
>> 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/

2014-01-17 23:40:55

by Chris Ball

[permalink] [raw]
Subject: Re: [PATCH] mmc: sdhci: fix possible scheduling while atomic

Hi, adding Aisheng,

On Fri, Jan 17 2014, Andrew Bresticker wrote:
> On Fri, Jan 17, 2014 at 3:11 PM, John Tobias <[email protected]> wrote:
>> There's an existing patch for that...
>> http://www.spinics.net/lists/arm-kernel/msg296596.html
>
> Ah, I see. Looks like it has yet to be picked up...

The patches aren't quite identical -- Andrew's leaves the
disable_irq() call in and Aisheng's removes it. Which should I take?

Thanks,

- Chris.
--
Chris Ball <[email protected]> <http://printf.net/>

2014-01-18 03:21:14

by Andrew Bresticker

[permalink] [raw]
Subject: Re: [PATCH] mmc: sdhci: fix possible scheduling while atomic

On Fri, Jan 17, 2014 at 3:40 PM, Chris Ball <[email protected]> wrote:
> Hi, adding Aisheng,
>
> On Fri, Jan 17 2014, Andrew Bresticker wrote:
>> On Fri, Jan 17, 2014 at 3:11 PM, John Tobias <[email protected]> wrote:
>>> There's an existing patch for that...
>>> http://www.spinics.net/lists/arm-kernel/msg296596.html
>>
>> Ah, I see. Looks like it has yet to be picked up...
>
> The patches aren't quite identical -- Andrew's leaves the
> disable_irq() call in and Aisheng's removes it. Which should I take?

Since the disable_irq() is now redundant, I suppose Aisheng's is more correct.

Thanks,
Andrew

>
> Thanks,
>
> - Chris.
> --
> Chris Ball <[email protected]> <http://printf.net/>

2014-01-18 03:40:54

by Chris Ball

[permalink] [raw]
Subject: Re: [PATCH] mmc: sdhci: fix possible scheduling while atomic

Hi,

On Sat, Jan 18 2014, Andrew Bresticker wrote:
>>>> There's an existing patch for that...
>>>> http://www.spinics.net/lists/arm-kernel/msg296596.html
>>>
>>> Ah, I see. Looks like it has yet to be picked up...
>>
>> The patches aren't quite identical -- Andrew's leaves the
>> disable_irq() call in and Aisheng's removes it. Which should I take?
>
> Since the disable_irq() is now redundant, I suppose Aisheng's is more correct

Thanks, pushed Aisheng's version to mmc-next for 3.14.

- Chris.
--
Chris Ball <[email protected]> <http://printf.net/>