Re: [PATCH 3/7] usb: mtu3: fix KE at qmu transfer done irq handler

[AngeloGioacchino Del Regno]

Il 07/04/23 09:59, Chunfeng Yun (云春峰) ha scritto:
> On Mon, 2023-04-03 at 14:31 +0200, AngeloGioacchino Del Regno wrote:
> > External email : Please do not click links or open attachments until
> > you have verified the sender or the content.
> >
> >
> > Il 03/04/23 04:52, Chunfeng Yun ha scritto:
> > > When handle qmu transfer irq, it will unlock @mtu->lock before give
> > > back
> > > request, if another thread hanlde 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
> >
> > KE == Kernel Error? I think you wanted to say KP == Kernel Panic
> > instead.
> >
> > Also, s/hanlder/handler/g.
> Ok, will modify it
> > > 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@xxxxxxxxxxxx>
> >
> > This is a fix and needs a Fixes tag.
> I usually add Fixes tag when the issue introduced by a patch except the
> original one when the driver applied.

If this patch is a fix for the "original driver", you shall still add a
Fixes tag which advertises that this fixes the first commit, so the driver
was broken from the very beginning.

Thanks,
Angelo.