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

[Doug Anderson]

Hi,

On Tue, Jan 28, 2020 at 2:15 PM Guenter Roeck <linux@xxxxxxxxxxxx> 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@xxxxxxxxxx>
> Cc: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
> Cc: Brian Norris <briannorris@xxxxxxxxxxxx>
> Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
>  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:

Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>