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Subject: Re: [PATCH] brcmfmac: pcie: fix oops on failure to resume and reprobe
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     Arend van Spriel <aspriel@gmail.com>,
        Franky Lin <franky.lin@broadcom.com>,
        Hante Meuleman <hante.meuleman@broadcom.com>,
        Chi-hsien Lin <chi-hsien.lin@infineon.com>,
        Wright Feng <wright.feng@infineon.com>,
        Chung-hsien Hsu <chung-hsien.hsu@infineon.com>,
        "kernel@pengutronix.de" <kernel@pengutronix.de>,
        "SHA-cyfmac-dev-list@infineon.com" <SHA-cyfmac-dev-list@infineon.com>,
        "brcm80211-dev-list.pdl@broadcom.com" 
        <brcm80211-dev-list.pdl@broadcom.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        Kalle Valo <kvalo@codeaurora.org>,
        Jakub Kicinski <kuba@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
References: <20210817063521.22450-1-a.fatoum@pengutronix.de>
 <CAHp75Vfc_T04p95PgVUd+CK+ttPwX2aOC4WPD35Z01WQV1MxKw@mail.gmail.com>
From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
Message-ID: <3a9a3789-5a13-7e72-b909-8f0826b8ab86@pengutronix.de>
Date:   Tue, 17 Aug 2021 13:11:31 +0200
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On 17.08.21 13:02, Andy Shevchenko wrote:
> On Tuesday, August 17, 2021, Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
> 
>> When resuming from suspend, brcmf_pcie_pm_leave_D3 will first attempt a
>> hot resume and then fall back to removing the PCI device and then
>> reprobing. If this probe fails, the kernel will oops, because brcmf_err,
>> which is called to report the failure will dereference the stale bus
>> pointer. Open code and use the default bus-less brcmf_err to avoid this.
>>
>> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
>> ---
>> To: Arend van Spriel <aspriel@gmail.com>
>> To: Franky Lin <franky.lin@broadcom.com>
>> To: Hante Meuleman <hante.meuleman@broadcom.com>
>> To: Chi-hsien Lin <chi-hsien.lin@infineon.com>
>> To: Wright Feng <wright.feng@infineon.com>
>> To: Chung-hsien Hsu <chung-hsien.hsu@infineon.com>
>> Cc: SHA-cyfmac-dev-list@infineon.com
>> Cc: brcm80211-dev-list.pdl@broadcom.com
>> Cc: netdev@vger.kernel.org
>> Cc: linux-wireless@vger.kernel.org
>> Cc: Kalle Valo <kvalo@codeaurora.org>
>> Cc: Jakub Kicinski <kuba@kernel.org>
>> Cc: "David S. Miller" <davem@davemloft.net>
>> Cc: linux-kernel@vger.kernel.org
>> ---
>>  drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
>> b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
>> index 9ef94d7a7ca7..d824bea4b79d 100644
>> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
>> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
>> @@ -2209,7 +2209,7 @@ static int brcmf_pcie_pm_leave_D3(struct device *dev)
>>
>>         err = brcmf_pcie_probe(pdev, NULL);
>>         if (err)
>> -               brcmf_err(bus, "probe after resume failed, err=%d\n", err);
>> +               __brcmf_err(NULL, __func__, "probe after resume failed,
>> err=%d\n",
> 
> 
> This is weird looking line now. Why can’t you simply use dev_err() /
> netdev_err()?

That's what brcmf_err normally expands to, but in this file the macro
is overridden to add the extra first argument.

The brcmf_ logging function write to brcmf trace buffers. This is not
done with netdev_err/dev_err (and replacing the existing logging
is out of scope for a regression fix anyway).

Cheers,
Ahmad

> 
> 
>>
>>         return err;
>>  }
>> --
>> 2.30.2
>>
>>
> 


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