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From: Andreas Persson <andreasp56@outlook.com>
To: Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Subject: [PATCH v2] mtd: cfi_cmdset_0002: fix crash when erasing/writing AMD cards
Date: Mon, 12 Jul 2021 09:54:52 +0200	[thread overview]
Message-ID: <DB6P189MB05830B3530B8087476C5CFE4C1159@DB6P189MB0583.EURP189.PROD.OUTLOOK.COM> (raw)

Erasing an AMD linear flash card (AM29F016D) crashes after the first
sector has been erased. Likewise, writing to it crashes after two bytes
have been written. The reason is a missing check for a null pointer -
the cmdset_priv field is not set for this type of card.

Fixes: 4844ef80305d ("mtd: cfi_cmdset_0002: Add support for polling status register")
Signed-off-by: Andreas Persson <andreasp56@outlook.com>
---
I posted this patch before, but I did some rookie mistakes, such as
only sending to the list and not to any maintainers. The patch format
was also broken. I hope it's better now. The actual code change is the
same.

 drivers/mtd/chips/cfi_cmdset_0002.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
index 3097e93787f7..a761134fd3be 100644
--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -119,7 +119,7 @@ static int cfi_use_status_reg(struct cfi_private *cfi)
 	struct cfi_pri_amdstd *extp = cfi->cmdset_priv;
 	u8 poll_mask = CFI_POLL_STATUS_REG | CFI_POLL_DQ;
 
-	return extp->MinorVersion >= '5' &&
+	return extp && extp->MinorVersion >= '5' &&
 		(extp->SoftwareFeatures & poll_mask) == CFI_POLL_STATUS_REG;
 }
 
-- 
2.30.2


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             reply	other threads:[~2021-07-12  7:56 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-12  7:54 Andreas Persson [this message]
2021-07-15 22:50 ` [PATCH v2] mtd: cfi_cmdset_0002: fix crash when erasing/writing AMD cards Miquel Raynal

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