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Date:   Sun, 23 Jan 2022 16:33:26 +0100
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Dan Carpenter <dan.carpenter@oracle.com>,
        Joern Engel <joern@lazybastard.org>,
        yangerkun <yangerkun@huawei.com>
Cc:     Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-mtd@lists.infradead.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH v2] mtd: phram: Prevent divide by zero bug in
 phram_setup()
Message-ID: <20220123163326.5ea97476@xps13>
In-Reply-To: <20220123152256.529296-1-miquel.raynal@bootlin.com>
References: <20220121115505.GI1978@kadam>
        <20220123152256.529296-1-miquel.raynal@bootlin.com>
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miquel.raynal@bootlin.com wrote on Sun, 23 Jan 2022 16:22:56 +0100:

> On Fri, 2022-01-21 at 11:55:05 UTC, Dan Carpenter wrote:
> > The problem is that "erasesize" is a uint64_t type so it might be
> > non-zero but the lower 32 bits are zero so when it's truncated,
> > "(uint32_t)erasesize", then that value is zero. This leads to a
> > divide by zero bug.
> > 
> > Avoid the bug by delaying the divide until after we have validated
> > that "erasesize" is non-zero and within the uint32_t range.
> > 
> > Fixes: dc2b3e5cbc80 ("mtd: phram: use div_u64_rem to stop overwrite len in phram_setup")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>  
> 
> Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks.

Pushed on mtd/fixes, actually.