All of lore.kernel.org
 help / color / mirror / Atom feed
From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Xiaoming Ni <nixiaoming@huawei.com>
Cc: wangle6@huawei.com, vigneshr@ti.com, tudor.ambarus@microchip.com,
	richard@nod.at, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org, linux-mtd@lists.infradead.org,
	gregkh@linuxfoundation.org, tglx@linutronix.de
Subject: Re: ping // [PATCH] mtd:cfi_cmdset_0002: fix atomic sleep bug when CONFIG_MTD_XIP=y
Date: Mon, 7 Dec 2020 11:53:30 +0100	[thread overview]
Message-ID: <20201207115228.0a6de398@xps13> (raw)
In-Reply-To: <a02e1364-3b82-039a-4b65-e2a216663dd4@huawei.com>

Hi Xiaoming,

Xiaoming Ni <nixiaoming@huawei.com> wrote on Mon, 7 Dec 2020 18:48:33
+0800:

> ping
> 
> On 2020/11/27 21:07, Xiaoming Ni wrote:
> > When CONFIG_MTD_XIP=y, local_irq_disable() is called in xip_disable().
> > To avoid sleep in interrupt context, we need to call local_irq_enable()
> > before schedule().
> > 
> > The problem call stack is as follows:
> > bug1:
> > 	do_write_oneword_retry()
> > 		xip_disable()
> > 			local_irq_disable()
> > 		do_write_oneword_once()
> > 			schedule()
> > bug2:
> > 	do_write_buffer()
> > 		xip_disable()
> > 			local_irq_disable()
> > 		do_write_buffer_wait()
> > 			schedule()
> > bug3:
> > 	do_erase_chip()
> > 		xip_disable()
> > 			local_irq_disable()
> > 		schedule()
> > bug4:
> > 	do_erase_oneblock()
> > 		xip_disable()
> > 			local_irq_disable()
> > 		schedule()
> > 
> > Fixes: 02b15e343aee ("[MTD] XIP for AMD CFI flash.")
> > Cc: stable@vger.kernel.org # v2.6.13
> > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> > ---
> >   drivers/mtd/chips/cfi_cmdset_0002.c | 16 ++++++++++++++++
> >   1 file changed, 16 insertions(+)
> > 
> > diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
> > index a1f3e1031c3d..12c3776f093a 100644
> > --- a/drivers/mtd/chips/cfi_cmdset_0002.c
> > +++ b/drivers/mtd/chips/cfi_cmdset_0002.c
> > @@ -1682,7 +1682,11 @@ static int __xipram do_write_oneword_once(struct map_info *map,
> >   			set_current_state(TASK_UNINTERRUPTIBLE);
> >   			add_wait_queue(&chip->wq, &wait);
> >   			mutex_unlock(&chip->mutex);
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_enable();
> >   			schedule();
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_disable();

The fix really seems strange to me. I will let Vignesh decide but I
think we should consider updating/fixing xip_disable instead.

> >   			remove_wait_queue(&chip->wq, &wait);
> >   			timeo = jiffies + (HZ / 2); /* FIXME */
> >   			mutex_lock(&chip->mutex);
> > @@ -1962,7 +1966,11 @@ static int __xipram do_write_buffer_wait(struct map_info *map,
> >   			set_current_state(TASK_UNINTERRUPTIBLE);
> >   			add_wait_queue(&chip->wq, &wait);
> >   			mutex_unlock(&chip->mutex);
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_enable();
> >   			schedule();
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_disable();
> >   			remove_wait_queue(&chip->wq, &wait);
> >   			timeo = jiffies + (HZ / 2); /* FIXME */
> >   			mutex_lock(&chip->mutex);
> > @@ -2461,7 +2469,11 @@ static int __xipram do_erase_chip(struct map_info *map, struct flchip *chip)
> >   			set_current_state(TASK_UNINTERRUPTIBLE);
> >   			add_wait_queue(&chip->wq, &wait);
> >   			mutex_unlock(&chip->mutex);
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_enable();
> >   			schedule();
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_disable();
> >   			remove_wait_queue(&chip->wq, &wait);
> >   			mutex_lock(&chip->mutex);
> >   			continue;
> > @@ -2560,7 +2572,11 @@ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
> >   			set_current_state(TASK_UNINTERRUPTIBLE);
> >   			add_wait_queue(&chip->wq, &wait);
> >   			mutex_unlock(&chip->mutex);
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_enable();
> >   			schedule();
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_disable();
> >   			remove_wait_queue(&chip->wq, &wait);
> >   			mutex_lock(&chip->mutex);
> >   			continue;
> >   
> 

Thanks,
Miquèl

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

WARNING: multiple messages have this Message-ID (diff)
From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Xiaoming Ni <nixiaoming@huawei.com>
Cc: <richard@nod.at>, <vigneshr@ti.com>,
	<tudor.ambarus@microchip.com>, <tglx@linutronix.de>,
	<linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
	<stable@vger.kernel.org>, <gregkh@linuxfoundation.org>,
	<wangle6@huawei.com>
Subject: Re: ping // [PATCH] mtd:cfi_cmdset_0002: fix atomic sleep bug when CONFIG_MTD_XIP=y
Date: Mon, 7 Dec 2020 11:53:30 +0100	[thread overview]
Message-ID: <20201207115228.0a6de398@xps13> (raw)
In-Reply-To: <a02e1364-3b82-039a-4b65-e2a216663dd4@huawei.com>

Hi Xiaoming,

Xiaoming Ni <nixiaoming@huawei.com> wrote on Mon, 7 Dec 2020 18:48:33
+0800:

> ping
> 
> On 2020/11/27 21:07, Xiaoming Ni wrote:
> > When CONFIG_MTD_XIP=y, local_irq_disable() is called in xip_disable().
> > To avoid sleep in interrupt context, we need to call local_irq_enable()
> > before schedule().
> > 
> > The problem call stack is as follows:
> > bug1:
> > 	do_write_oneword_retry()
> > 		xip_disable()
> > 			local_irq_disable()
> > 		do_write_oneword_once()
> > 			schedule()
> > bug2:
> > 	do_write_buffer()
> > 		xip_disable()
> > 			local_irq_disable()
> > 		do_write_buffer_wait()
> > 			schedule()
> > bug3:
> > 	do_erase_chip()
> > 		xip_disable()
> > 			local_irq_disable()
> > 		schedule()
> > bug4:
> > 	do_erase_oneblock()
> > 		xip_disable()
> > 			local_irq_disable()
> > 		schedule()
> > 
> > Fixes: 02b15e343aee ("[MTD] XIP for AMD CFI flash.")
> > Cc: stable@vger.kernel.org # v2.6.13
> > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> > ---
> >   drivers/mtd/chips/cfi_cmdset_0002.c | 16 ++++++++++++++++
> >   1 file changed, 16 insertions(+)
> > 
> > diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
> > index a1f3e1031c3d..12c3776f093a 100644
> > --- a/drivers/mtd/chips/cfi_cmdset_0002.c
> > +++ b/drivers/mtd/chips/cfi_cmdset_0002.c
> > @@ -1682,7 +1682,11 @@ static int __xipram do_write_oneword_once(struct map_info *map,
> >   			set_current_state(TASK_UNINTERRUPTIBLE);
> >   			add_wait_queue(&chip->wq, &wait);
> >   			mutex_unlock(&chip->mutex);
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_enable();
> >   			schedule();
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_disable();

The fix really seems strange to me. I will let Vignesh decide but I
think we should consider updating/fixing xip_disable instead.

> >   			remove_wait_queue(&chip->wq, &wait);
> >   			timeo = jiffies + (HZ / 2); /* FIXME */
> >   			mutex_lock(&chip->mutex);
> > @@ -1962,7 +1966,11 @@ static int __xipram do_write_buffer_wait(struct map_info *map,
> >   			set_current_state(TASK_UNINTERRUPTIBLE);
> >   			add_wait_queue(&chip->wq, &wait);
> >   			mutex_unlock(&chip->mutex);
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_enable();
> >   			schedule();
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_disable();
> >   			remove_wait_queue(&chip->wq, &wait);
> >   			timeo = jiffies + (HZ / 2); /* FIXME */
> >   			mutex_lock(&chip->mutex);
> > @@ -2461,7 +2469,11 @@ static int __xipram do_erase_chip(struct map_info *map, struct flchip *chip)
> >   			set_current_state(TASK_UNINTERRUPTIBLE);
> >   			add_wait_queue(&chip->wq, &wait);
> >   			mutex_unlock(&chip->mutex);
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_enable();
> >   			schedule();
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_disable();
> >   			remove_wait_queue(&chip->wq, &wait);
> >   			mutex_lock(&chip->mutex);
> >   			continue;
> > @@ -2560,7 +2572,11 @@ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
> >   			set_current_state(TASK_UNINTERRUPTIBLE);
> >   			add_wait_queue(&chip->wq, &wait);
> >   			mutex_unlock(&chip->mutex);
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_enable();
> >   			schedule();
> > +			if (IS_ENABLED(CONFIG_MTD_XIP))
> > +				local_irq_disable();
> >   			remove_wait_queue(&chip->wq, &wait);
> >   			mutex_lock(&chip->mutex);
> >   			continue;
> >   
> 

Thanks,
Miquèl

  reply	other threads:[~2020-12-07 10:54 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-27 13:07 [PATCH] mtd:cfi_cmdset_0002: fix atomic sleep bug when CONFIG_MTD_XIP=y Xiaoming Ni
2020-11-27 13:07 ` Xiaoming Ni
2020-12-07 10:48 ` ping // " Xiaoming Ni
2020-12-07 10:48   ` Xiaoming Ni
2020-12-07 10:53   ` Miquel Raynal [this message]
2020-12-07 10:53     ` Miquel Raynal
2020-12-07 18:59     ` Vignesh Raghavendra
2020-12-07 18:59       ` Vignesh Raghavendra
2020-12-08  1:23       ` Xiaoming Ni
2020-12-08  1:23         ` Xiaoming Ni
2020-12-14  7:16         ` Vignesh Raghavendra
2020-12-14  7:16           ` Vignesh Raghavendra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201207115228.0a6de398@xps13 \
    --to=miquel.raynal@bootlin.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mtd@lists.infradead.org \
    --cc=nixiaoming@huawei.com \
    --cc=richard@nod.at \
    --cc=stable@vger.kernel.org \
    --cc=tglx@linutronix.de \
    --cc=tudor.ambarus@microchip.com \
    --cc=vigneshr@ti.com \
    --cc=wangle6@huawei.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.