Messages in this thread | | | Subject | Re: [PATCH 1/2] gpio: gpio-grgpio: fix possible sleep-in-atomic-context bugs in grgpio_remove() | From | Jia-Ju Bai <> | Date | Thu, 19 Dec 2019 20:35:58 +0800 |
| |
On 2019/12/19 19:10, Bartosz Golaszewski wrote: > śr., 18 gru 2019 o 14:26 Jia-Ju Bai <baijiaju1990@gmail.com> napisał(a): >> The driver may sleep while holding a spinlock. >> The function call path (from bottom to top) in Linux 4.19 is: >> >> drivers/gpio/gpiolib-sysfs.c, 796: >> mutex_lock in gpiochip_sysfs_unregister >> drivers/gpio/gpiolib.c, 1455: >> gpiochip_sysfs_unregister in gpiochip_remove >> drivers/gpio/gpio-grgpio.c, 460: >> gpiochip_remove in grgpio_remove >> drivers/gpio/gpio-grgpio.c, 449: >> _raw_spin_lock_irqsave in grgpio_remove >> >> kernel/irq/irqdomain.c, 243: >> mutex_lock in irq_domain_remove >> drivers/gpio/gpio-grgpio.c, 463: >> irq_domain_remove in grgpio_remove >> drivers/gpio/gpio-grgpio.c, 449: >> _raw_spin_lock_irqsave in grgpio_remove >> >> mutex_lock() can sleep at runtime. >> >> To fix these bugs, gpiochip_remove() and irq_domain_remove() are called >> without holding the spinlock. >> >> These bugs are found by a static analysis tool STCheck written by myself. >> >> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> >> --- >> drivers/gpio/gpio-grgpio.c | 5 ++++- >> sound/soc/sti/uniperif_player.c | 3 ++- >> 2 files changed, 6 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpio/gpio-grgpio.c b/drivers/gpio/gpio-grgpio.c >> index 08234e64993a..60a2871c5ba7 100644 >> --- a/drivers/gpio/gpio-grgpio.c >> +++ b/drivers/gpio/gpio-grgpio.c >> @@ -448,13 +448,16 @@ static int grgpio_remove(struct platform_device *ofdev) >> } >> } >> >> + spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); >> + >> gpiochip_remove(&priv->gc); >> >> if (priv->domain) >> irq_domain_remove(priv->domain); >> >> out: >> - spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); >> + if (ret) >> + spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); > In general there is no need for locking in remove() callbacks. I guess > you can safely remove the spinlock here all together.
Okay, I will send a new patch.
> >> return ret; >> } >> diff --git a/sound/soc/sti/uniperif_player.c b/sound/soc/sti/uniperif_player.c >> index 48ea915b24ba..62244e207679 100644 >> --- a/sound/soc/sti/uniperif_player.c >> +++ b/sound/soc/sti/uniperif_player.c >> @@ -601,13 +601,14 @@ static int uni_player_ctl_iec958_put(struct snd_kcontrol *kcontrol, >> mutex_unlock(&player->ctrl_lock); >> >> spin_lock_irqsave(&player->irq_lock, flags); >> + spin_unlock_irqrestore(&player->irq_lock, flags); > Yeah I can tell this was generated automatically - what does this line > is expected to achieve?
Ah, sorry, this is my mistake. I forgot to reset the kernel code before writing the patch...
Best wishes, Jia-Ju Bai
| |