[PATCH v2 3/7] usb: mtu3: fix kernel panic at qmu transfer done irq handler

[AngeloGioacchino Del Regno]

Il 07/04/23 10:29, Chunfeng Yun ha scritto:
> When handle qmu transfer irq, it will unlock @mtu->lock before give back
> request, if another thread handle disconnect event at the same time, and
> try to disable ep, it may lock @mtu->lock and free qmu ring, then qmu
> irq hanlder may get a NULL gpd, avoid the KE by checking gpd's value before
> handling it.
> 
> e.g.
> qmu done irq on cpu0                 thread running on cpu1
> 
> qmu_done_tx()
>    handle gpd [0]
>      mtu3_requ_complete()        mtu3_gadget_ep_disable()
>        unlock @mtu->lock
>          give back request         lock @mtu->lock
>                                      mtu3_ep_disable()
>                                        mtu3_gpd_ring_free()
>                                     unlock @mtu->lock
>        lock @mtu->lock
>      get next gpd [1]
> 
> [1]: goto [0] to handle next gpd, and next gpd may be NULL.
> 
> Signed-off-by: Chunfeng Yun <chunfeng.yun at mediatek.com>

NACK. You still miss the Fixes tag.

Regards,
Angelo