* [BUG] drivers/gpio: some possible sleep-in-atomic bugs
@ 2017-12-12 3:59 Jia-Ju Bai
2017-12-13 16:18 ` Andreas Larsson
0 siblings, 1 reply; 2+ messages in thread
From: Jia-Ju Bai @ 2017-12-12 3:59 UTC (permalink / raw)
To: linus.walleij, andreas; +Cc: linux-gpio, Linux Kernel Mailing List
According to drivers/gpio/gpio-grgpio.c, the kernel module may sleep
under a spinlock.
The function call paths are:
grgpio_remove (acquire the spinlock)
gpiochip_remove
gpiochip_sysfs_unregister
device_unregister --> may sleep
mutex_lock --> may sleep
grgpio_remove (acquire the spinlock)
gpiochip_remove
gpiochip_sysfs_unregister
gpiod_free
__gpiod_free
gpiod_unexport
device_unregister --> may sleep
mutex_lock --> may sleep
grgpio_remove (acquire the spinlock)
irq_domain_remove
mutex_lock --> may sleep
grgpio_irq_map (acquire the spinlock)
request_irq --> may sleep
grgpio_irq_unmap (acquire the spinlock)
free_irq --> may sleep
I do not find a good way to fix them, so I only report.
These possible bugs is found by my static analysis tool (DSAC) and
checked by my code review.
Thanks,
Jia-Ju Bai
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [BUG] drivers/gpio: some possible sleep-in-atomic bugs
2017-12-12 3:59 [BUG] drivers/gpio: some possible sleep-in-atomic bugs Jia-Ju Bai
@ 2017-12-13 16:18 ` Andreas Larsson
0 siblings, 0 replies; 2+ messages in thread
From: Andreas Larsson @ 2017-12-13 16:18 UTC (permalink / raw)
To: Jia-Ju Bai, linus.walleij; +Cc: linux-gpio, Linux Kernel Mailing List
On 2017-12-12 04:59, Jia-Ju Bai wrote:
> According to drivers/gpio/gpio-grgpio.c, the kernel module may sleep
> under a spinlock.
> The function call paths are:
> grgpio_remove (acquire the spinlock)
> gpiochip_remove
> gpiochip_sysfs_unregister
> device_unregister --> may sleep
> mutex_lock --> may sleep
>
> grgpio_remove (acquire the spinlock)
> gpiochip_remove
> gpiochip_sysfs_unregister
> gpiod_free
> __gpiod_free
> gpiod_unexport
> device_unregister --> may sleep
> mutex_lock --> may sleep
>
> grgpio_remove (acquire the spinlock)
> irq_domain_remove
> mutex_lock --> may sleep
>
> grgpio_irq_map (acquire the spinlock)
> request_irq --> may sleep
>
> grgpio_irq_unmap (acquire the spinlock)
> free_irq --> may sleep
>
>
> I do not find a good way to fix them, so I only report.
> These possible bugs is found by my static analysis tool (DSAC) and
> checked by my code review.
Hi!
Thank you for reporting this. I will take a look at it.
--
Best Regards,
Andreas Larsson
^ permalink raw reply [flat|nested] 2+ messages in thread
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2017-12-12 3:59 [BUG] drivers/gpio: some possible sleep-in-atomic bugs Jia-Ju Bai
2017-12-13 16:18 ` Andreas Larsson
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