On Wed, Mar 27, 2024 at 02:08:27PM +0100, Stefan Sperling wrote: > On Tue, Mar 26, 2024 at 11:05:49PM +0100, Patrick Wildt wrote: > > On Fri, Mar 01, 2024 at 12:00:29AM +0100, Alexander Bluhm wrote: > > > Hi, > > > > > > When doing flood ping transmit from a machine and simultaneously > > > ifconfig down/up in a loop, dwqe(4) interface driver crashes. > > > * Don't run TX/RX proc in case the interface is down? > > The RX path already has a corresponding check. But the Tx path does not. > > If the problem is a race involving mbufs freed via dwqe_down() and > mbufs freed via dwqe_tx_proc() then this simple tweak might help.
With this patch bluhm's test machine has survived 30 minutes of flood ping + ifconfig down/up in a loop. Without the patch the machine crashes within a few seconds. I understand that there could be an issue in intr_barrier() which gets papered over by this patch. However the patch does avoid the crash and it is trivial to revert when testing the effectiveness of any potential intr_barrier() fixes. ok? > diff /usr/src > commit - 029d0a842cd8a317375b31145383409491d345e7 > path + /usr/src > blob - 97f874d2edf74a009a811455fbf37ca56f725eef > file + sys/dev/ic/dwqe.c > --- sys/dev/ic/dwqe.c > +++ sys/dev/ic/dwqe.c > @@ -593,6 +593,9 @@ dwqe_tx_proc(struct dwqe_softc *sc) > struct dwqe_buf *txb; > int idx, txfree; > > + if ((ifp->if_flags & IFF_RUNNING) == 0) > + return; > + > bus_dmamap_sync(sc->sc_dmat, DWQE_DMA_MAP(sc->sc_txring), 0, > DWQE_DMA_LEN(sc->sc_txring), > BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE); > > > >
