ping // [PATCH] mtd:cfi_cmdset_0002: fix atomic sleep bug when CONFIG_MTD_XIP=y

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();
  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;