On 4/3/22 12:49, Fabio M. De Francesco wrote:
On domenica 3 aprile 2022 12:43:04 CEST Fabio M. De Francesco wrote:
On sabato 2 aprile 2022 22:47:27 CEST Michael Straube wrote:
Hi all,
smatch reported a sleeping in atomic context.
rtw_set_802_11_disassociate() <- disables preempt
-> _rtw_pwr_wakeup()
-> ips_leave()
rtw_set_802_11_disassociate() takes a spinlock and ips_leave() uses a
mutex.
I'm fairly new to the locking stuff, but as far as I know this is not a
false positive since mutex can sleep, but that's not allowed under a
spinlock.
What is the best way to handle this?
I'm not sure if converting the mutex to a spinlock (including all the
other places where the mutex is used) is the right thing to do?
thanks,
Michael
Hi Michael,
No, this is a false positive: ips_leave is never called under spinlocks.
Some time ago I blindly trusted Smatch and submitted a patch for what you
are reporting just now again. Soon after submission I realized it and
then I had to ask Greg to discard my patch.
Please read the related thread:
[PATCH] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context
https://lore.kernel.org/lkml/20220206225943.7848-1-fmdefrancesco@xxxxxxxxx/
Thanks,
Fabio
I'm sorry, the correct link is the following:
[PATCH v2 2/2] staging: r8188eu: Use kzalloc() with GFP_ATOMIC in atomic context
https://lore.kernel.org/lkml/20220208180426.27455-3-fmdefrancesco@xxxxxxxxx/
Fabio
Hi Fabio,
Ah I see now, thanks. Well, I think the code is not very clear and easy
to follow here. Perhaps we should refactor this area someday to avoid
future confusions.
regards,
Michael
