2018-09-01 09:11:26

by Jia-Ju Bai

Subject: [BUG] net: wireless: mwifiex: A possible sleep-in-atomic-context bug in mwifiex_wait_queue_complete()

mwifiex_usb_tx_complete() is a completion handler function for the
USB driver. So it should not sleep, but it is can sleep according to the
function call paths (from bottom to top) in Linux-4.16:

[FUNC] schedule_timeout
drivers/net/wireless/marvell/mwifiex/sta_ioctl.c, 63:
schedule_timeout in mwifiex_wait_queue_complete
drivers/net/wireless/marvell/mwifiex/cmdevt.c, 673:
mwifiex_wait_queue_complete in mwifiex_send_cmd
drivers/net/wireless/marvell/mwifiex/main.c, 1046:
mwifiex_send_cmd in mwifiex_multi_chan_resync
drivers/net/wireless/marvell/mwifiex/usb.c, 288:
mwifiex_multi_chan_resync in mwifiex_usb_tx_complete

I do not find a good way to fix this bug, so I only report it.

This bug is found by my static analysis tool DSAC.


Best wishes,
Jia-Ju Bai

2018-09-03 06:43:16

by Ganapathi Bhat

Subject: RE: [EXT] [BUG] net: wireless: mwifiex: A possible sleep-in-atomic-context bug in mwifiex_wait_queue_complete()

Hi Jia-Ju,

>
> [FUNC] schedule_timeout
> drivers/net/wireless/marvell/mwifiex/sta_ioctl.c, 63:
> schedule_timeout in mwifiex_wait_queue_complete
> drivers/net/wireless/marvell/mwifiex/cmdevt.c, 673:
> mwifiex_wait_queue_complete in mwifiex_send_cmd
Here, mwifiex_send_cmd does not call mwifiex_wait_queue_complete, because the sync parameter is false.
Note that the function mwifiex_multi_chan_resync did call mwifiex_send_cmd with sync = false.
> drivers/net/wireless/marvell/mwifiex/main.c, 1046:
> mwifiex_send_cmd in mwifiex_multi_chan_resync
> drivers/net/wireless/marvell/mwifiex/usb.c, 288:
> mwifiex_multi_chan_resync in mwifiex_usb_tx_complete
>
Thanks,
Ganapathi

2018-09-03 07:36:48

by Jia-Ju Bai

Subject: Re: [EXT] [BUG] net: wireless: mwifiex: A possible sleep-in-atomic-context bug in mwifiex_wait_queue_complete()

On 2018/9/3 14:41, Ganapathi Bhat wrote:
> Hi Jia-Ju,
>
>> [FUNC] schedule_timeout
>> drivers/net/wireless/marvell/mwifiex/sta_ioctl.c, 63:
>> schedule_timeout in mwifiex_wait_queue_complete
>> drivers/net/wireless/marvell/mwifiex/cmdevt.c, 673:
>> mwifiex_wait_queue_complete in mwifiex_send_cmd
> Here, mwifiex_send_cmd does not call mwifiex_wait_queue_complete, because the sync parameter is false.
> Note that the function mwifiex_multi_chan_resync did call mwifiex_send_cmd with sync = false.

Thanks for the reply.
I check the code again, and find my report it false, sorry for that.


Best wishes,
Jia-Ju Bai