linux-kernel - Re: [PATCH] brcmfmac: abort and release host after error

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Message-ID: <CA+8PC_f=qCUjihwbjd3vtGaNkG-=R1qm83oS7AmgtLTy6EgjyQ@mail.gmail.com>
Date:   Tue, 28 Jan 2020 16:57:59 -0800
From:   Franky Lin <franky.lin@...adcom.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Doug Anderson <dianders@...omium.org>,
        Kalle Valo <kvalo@...eaurora.org>,
        Arend van Spriel <arend.vanspriel@...adcom.com>,
        Hante Meuleman <hante.meuleman@...adcom.com>,
        Chi-Hsien Lin <chi-hsien.lin@...ress.com>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        linux-wireless <linux-wireless@...r.kernel.org>,
        "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER" 
        <brcm80211-dev-list.pdl@...adcom.com>,
        brcm80211-dev-list <brcm80211-dev-list@...ress.com>,
        netdev <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        Brian Norris <briannorris@...omium.org>
Subject: Re: [PATCH] brcmfmac: abort and release host after error

On Tue, Jan 28, 2020 at 4:05 PM Guenter Roeck <linux@...ck-us.net> wrote:
>
> On Tue, Jan 28, 2020 at 03:14:45PM -0800, Doug Anderson wrote:
> > Hi,
> >
> > On Tue, Jan 28, 2020 at 2:15 PM Guenter Roeck <linux@...ck-us.net> wrote:
> > >
> > > With commit 216b44000ada ("brcmfmac: Fix use after free in
> > > brcmf_sdio_readframes()") applied, we see locking timeouts in
> > > brcmf_sdio_watchdog_thread().
> > >
> > > brcmfmac: brcmf_escan_timeout: timer expired
> > > INFO: task brcmf_wdog/mmc1:621 blocked for more than 120 seconds.
> > > Not tainted 4.19.94-07984-g24ff99a0f713 #1
> > > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> > > brcmf_wdog/mmc1 D    0   621      2 0x00000000 last_sleep: 2440793077.  last_runnable: 2440766827
> > > [<c0aa1e60>] (__schedule) from [<c0aa2100>] (schedule+0x98/0xc4)
> > > [<c0aa2100>] (schedule) from [<c0853830>] (__mmc_claim_host+0x154/0x274)
> > > [<c0853830>] (__mmc_claim_host) from [<bf10c5b8>] (brcmf_sdio_watchdog_thread+0x1b0/0x1f8 [brcmfmac])
> > > [<bf10c5b8>] (brcmf_sdio_watchdog_thread [brcmfmac]) from [<c02570b8>] (kthread+0x178/0x180)
> > >
> > > In addition to restarting or exiting the loop, it is also necessary to
> > > abort the command and to release the host.
> > >
> > > Fixes: 216b44000ada ("brcmfmac: Fix use after free in brcmf_sdio_readframes()")
> > > Cc: Dan Carpenter <dan.carpenter@...cle.com>
> > > Cc: Matthias Kaehlcke <mka@...omium.org>
> > > Cc: Brian Norris <briannorris@...omium.org>
> > > Cc: Douglas Anderson <dianders@...omium.org>
> > > Signed-off-by: Guenter Roeck <linux@...ck-us.net>
> > > ---
> > >  drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> > > index f9df95bc7fa1..2e1c23c7269d 100644
> > > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> > > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> > > @@ -1938,6 +1938,8 @@ static uint brcmf_sdio_readframes(struct brcmf_sdio *bus, uint maxframes)
> > >                         if (brcmf_sdio_hdparse(bus, bus->rxhdr, &rd_new,
> > >                                                BRCMF_SDIO_FT_NORMAL)) {
> > >                                 rd->len = 0;
> > > +                               brcmf_sdio_rxfail(bus, true, true);
> > > +                               sdio_release_host(bus->sdiodev->func1);
> >
> > I don't know much about this driver so I don't personally know if
> > "true, true" is the correct thing to pass to brcmf_sdio_rxfail(), but
> > it seems plausible.  Definitely the fix to call sdio_release_host() is
> > sane.
> >
> > Thus, unless someone knows for sure that brcmf_sdio_rxfail()'s
> > parameters should be different:
> >
> Actually, looking at brcmf_sdio_hdparse() and its other callers,
> I think it may not be needed at all - other callers don't do it, and
> there already are some calls to brcmf_sdio_rxfail() in that function.
> It would be nice though to get a confirmation before I submit v2.

I think invoking rxfail with both abort and NACK set to true is the
right thing to do here so that the pipeline can be properly purged.

Thanks!

Acked-by: franky.lin@...adcom.com