Re: [PATCH] netdev: fix crash in the RSSI polling fallback workaround

[Denis Kenzior <denkenz@gmail.com>]

Hi James,

On 10/3/24 7:58 AM, James Prestwood wrote:
> Prior to adding the polling fallback this code path was only used for
> signal level list notifications and netdev_rssi_polling_update() was
> structured as such, where if the RSSI list feature existed there was
> nothing to be done as the kernel handled the notifications.
> 
> For certain mediatek cards this is broken, hence why the fallback was
> added. But netdev_rssi_polling_update() was never changed to take
> this into account which bypassed the timer cleanup on disconnections
> resulting in a crash when the timer fired after IWD was disconnected:
> 
> iwd: ++++++++ backtrace ++++++++
> iwd: #0  0x7b5459642520 in /lib/x86_64-linux-gnu/libc.so.6
> iwd: #1  0x7b54597aedf4 in /lib/x86_64-linux-gnu/libc.so.6
> iwd: #2  0x49f82d in l_netlink_message_append() at ome/jprestwood/iwd/ell/netlink.c:825
> iwd: #3  0x4a0c12 in l_genl_msg_append_attr() at ome/jprestwood/iwd/ell/genl.c:1522
> iwd: #4  0x405c61 in netdev_rssi_poll() at ome/jprestwood/iwd/src/netdev.c:764
> iwd: #5  0x49cce4 in timeout_callback() at ome/jprestwood/iwd/ell/timeout.c:70
> iwd: #6  0x49c2ed in l_main_iterate() at ome/jprestwood/iwd/ell/main.c:455 (discriminator 2)
> iwd: #7  0x49c3bc in l_main_run() at ome/jprestwood/iwd/ell/main.c:504
> iwd: #8  0x49c5f0 in l_main_run_with_signal() at ome/jprestwood/iwd/ell/main.c:632
> iwd: #9  0x4049ed in main() at ome/jprestwood/iwd/src/main.c:614
> iwd: #10 0x7b5459629d90 in /lib/x86_64-linux-gnu/libc.so.6
> iwd: #11 0x7b5459629e40 in /lib/x86_64-linux-gnu/libc.so.6
> iwd: +++++++++++++++++++++++++++
> 
> To fix this we need to add checks for the cqm_poll_fallback flag in
> netdev_rssi_polling_update().
> ---
>   src/netdev.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 

Applied, thanks.

Regards,
-Denis