linux-kernel - Re: [PATCH V2] brcmfmac: stop watchdog before detach and free everything

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Message-ID: <CAHp75VfZoUV7u5JhquPrfE8qMWH8dv4WBaSvsy9H0DOS6vW6BA@mail.gmail.com>
Date:   Wed, 20 Jun 2018 16:15:32 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Michael Trimarchi <michael@...rulasolutions.com>
Cc:     Arend van Spriel <arend.vanspriel@...adcom.com>,
        Franky Lin <franky.lin@...adcom.com>,
        Hante Meuleman <hante.meuleman@...adcom.com>,
        Chi-Hsien Lin <chi-hsien.lin@...ress.com>,
        Wright Feng <wright.feng@...ress.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        "David S. Miller" <davem@...emloft.net>,
        Pieter-Paul Giesberts <pieter-paul.giesberts@...adcom.com>,
        Ian Molton <ian@...menth.co.uk>,
        "open list:TI WILINK WIRELES..." <linux-wireless@...r.kernel.org>,
        "open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER" 
        <brcm80211-dev-list.pdl@...adcom.com>,
        brcm80211-dev-list@...ress.com, netdev <netdev@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2] brcmfmac: stop watchdog before detach and free everything

On Wed, May 30, 2018 at 12:06 PM, Michael Trimarchi
<michael@...rulasolutions.com> wrote:
> Using built-in in kernel image without a firmware in filesystem
> or in the kernel image can lead to a kernel NULL pointer deference.
> Watchdog need to be stopped in brcmf_sdio_remove
>
> The system is going down NOW!
> [ 1348.110759] Unable to handle kernel NULL pointer dereference at virtual address 000002f8
> Sent SIGTERM to all processes
> [ 1348.121412] Mem abort info:
> [ 1348.126962]   ESR = 0x96000004
> [ 1348.130023]   Exception class = DABT (current EL), IL = 32 bits
> [ 1348.135948]   SET = 0, FnV = 0
> [ 1348.138997]   EA = 0, S1PTW = 0
> [ 1348.142154] Data abort info:
> [ 1348.145045]   ISV = 0, ISS = 0x00000004
> [ 1348.148884]   CM = 0, WnR = 0
> [ 1348.151861] user pgtable: 4k pages, 48-bit VAs, pgdp = (____ptrval____)
> [ 1348.158475] [00000000000002f8] pgd=0000000000000000
> [ 1348.163364] Internal error: Oops: 96000004 [#1] PREEMPT SMP
> [ 1348.168927] Modules linked in: ipv6
> [ 1348.172421] CPU: 3 PID: 1421 Comm: brcmf_wdog/mmc0 Not tainted 4.17.0-rc5-next-20180517 #18
> [ 1348.180757] Hardware name: Amarula A64-Relic (DT)
> [ 1348.185455] pstate: 60000005 (nZCv daif -PAN -UAO)
> [ 1348.190251] pc : brcmf_sdiod_freezer_count+0x0/0x20
> [ 1348.195124] lr : brcmf_sdio_watchdog_thread+0x64/0x290
> [ 1348.200253] sp : ffff00000b85be30
> [ 1348.203561] x29: ffff00000b85be30 x28: 0000000000000000
> [ 1348.208868] x27: ffff00000b6cb918 x26: ffff80003b990638
> [ 1348.214176] x25: ffff0000087b1a20 x24: ffff80003b94f800
> [ 1348.219483] x23: ffff000008e620c8 x22: ffff000008f0b660
> [ 1348.224790] x21: ffff000008c6a858 x20: 00000000fffffe00
> [ 1348.230097] x19: ffff80003b94f800 x18: 0000000000000001
> [ 1348.235404] x17: 0000ffffab2e8a74 x16: ffff0000080d7de8
> [ 1348.240711] x15: 0000000000000000 x14: 0000000000000400
> [ 1348.246018] x13: 0000000000000400 x12: 0000000000000001
> [ 1348.251324] x11: 00000000000002c4 x10: 0000000000000a10
> [ 1348.256631] x9 : ffff00000b85bc40 x8 : ffff80003be11870
> [ 1348.261937] x7 : ffff80003dfc7308 x6 : 000000078ff08b55
> [ 1348.267243] x5 : 00000139e1058400 x4 : 0000000000000000
> [ 1348.272550] x3 : dead000000000100 x2 : 958f2788d6618100
> [ 1348.277856] x1 : 00000000fffffe00 x0 : 0000000000000000
>

It was a 100% (or so) reproducible on Intel Edison with vanilla kernel
and linux-firmware package, while calibration file (*.txt) is not in
distribution.

The system is going down NOW!
Sent SIGTERM to all processes
[  118.695900] PGD 800000003bc3f067 P4D 800000003bc3f067 PUD 3bc5b067 PMD 0
[  118.695935] Oops: 0002 [#1] SMP PTI
[  118.711905] CPU: 1 PID: 1255 Comm: brcmf_wdog/mmc2 Not tainted
4.18.0-rc1-next-20180618+ #59
[  118.720354] Hardware name: Intel Corporation Merrifield/BODEGA BAY,
BIOS 542 2015.01.21:18.19.48
[  118.729181] RIP: 0010:brcmf_sdiod_freezer_count+0x7/0x10 [brcmfmac]

After this patch applied problem was gone

Tested-by: Andy Shevchenko <andy.shevchenko@...il.com>

P.S. Sorry it took a bit longer.

> Signed-off-by: Michael Trimarchi <michael@...rulasolutions.com>
> ---
>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> index 412a05b..061f69d 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> @@ -4294,6 +4294,13 @@ void brcmf_sdio_remove(struct brcmf_sdio *bus)
>         brcmf_dbg(TRACE, "Enter\n");
>
>         if (bus) {
> +               /* Stop watchdog task */
> +               if (bus->watchdog_tsk) {
> +                       send_sig(SIGTERM, bus->watchdog_tsk, 1);
> +                       kthread_stop(bus->watchdog_tsk);
> +                       bus->watchdog_tsk = NULL;
> +               }
> +
>                 /* De-register interrupt handler */
>                 brcmf_sdiod_intr_unregister(bus->sdiodev);
>
> --
> 2.7.4



-- 
With Best Regards,
Andy Shevchenko