Re: [PATCH v3 3/5] mtd: rawnand: brcmnand: Fix crash during the panic_write

From: William Zhang <william.zhang@broadcom.com>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Broadcom Kernel List <bcm-kernel-feedback-list@broadcom.com>,
	Linux MTD List <linux-mtd@lists.infradead.org>,
	f.fainelli@gmail.com, rafal@milecki.pl, kursad.oney@broadcom.com,
	joel.peshkin@broadcom.com, computersforpeace@gmail.com,
	anand.gore@broadcom.com, dregan@mail.com,
	kamal.dasu@broadcom.com, tomer.yacoby@broadcom.com,
	dan.beygelman@broadcom.com,
	Florian Fainelli <florian.fainelli@broadcom.com>,
	linux-kernel@vger.kernel.org,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Richard Weinberger <richard@nod.at>,
	Kamal Dasu <kdasu.kdev@gmail.com>
Subject: Re: [PATCH v3 3/5] mtd: rawnand: brcmnand: Fix crash during the panic_write
Date: Tue, 4 Jul 2023 17:40:03 -0700	[thread overview]
Message-ID: <287ecf48-9a8b-6cca-2888-37f6c71c4b39@broadcom.com> (raw)
In-Reply-To: <20230704172604.6924d2af@xps-13>

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Hi Miquel,

On 07/04/2023 08:26 AM, Miquel Raynal wrote:
> Hi William,
> 
> william.zhang@broadcom.com wrote on Tue, 27 Jun 2023 12:37:36 -0700:
> 
>> During the panic write path to execute another nand command, if
>> there is a pending command, we should wait for the command instead of
>> calling BUG_ON so we don't crash while crashing.
>>
>> Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller")
> 
> The Fixes tag looks wrong.
> 
The brcmnand_send_cmd function and BUG_ON line were added by this commit 
and the function didn't changed much since then. Not sure why you think 
it is wrong?

>> Signed-off-by: William Zhang <william.zhang@broadcom.com>
>> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
>> Reviewed-by: Kursad Oney <kursad.oney@broadcom.com>
>> Reviewed-by: Kamal Dasu <kamal.dasu@broadcom.com>
>> ---
>>
>> Changes in v3: None
>> Changes in v2: None
>>
>>   drivers/mtd/nand/raw/brcmnand/brcmnand.c | 12 +++++++++++-
>>   1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
>> index 37c2c7cfa00e..ea03104692bf 100644
>> --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
>> +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
>> @@ -1608,7 +1608,17 @@ static void brcmnand_send_cmd(struct brcmnand_host *host, int cmd)
>>   
>>   	dev_dbg(ctrl->dev, "send native cmd %d addr 0x%llx\n", cmd, cmd_addr);
>>   
>> -	BUG_ON(ctrl->cmd_pending != 0);
>> +	/*
>> +	 * If we came here through _panic_write and there is a pending
>> +	 * command, try to wait for it. If it times out, rather than
>> +	 * hitting BUG_ON, just return so we don't crash while crashing.
>> +	 */
>> +	if (oops_in_progress) {
>> +		if (ctrl->cmd_pending &&
>> +			bcmnand_ctrl_poll_status(ctrl, NAND_CTRL_RDY, NAND_CTRL_RDY, 0))
>> +			return;
>> +	} else
>> +		BUG_ON(ctrl->cmd_pending != 0);
>>   	ctrl->cmd_pending = cmd;
>>   
>>   	ret = bcmnand_ctrl_poll_status(ctrl, NAND_CTRL_RDY, NAND_CTRL_RDY, 0);
> 
> 
> Thanks,
> Miquèl
> 

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