[PATCH] mtd: rawnand: meson: Fix a potential double free issue

[PATCH] mtd: rawnand: meson: Fix a potential double free issue

[Christophe JAILLET]

When meson_nfc_nand_chip_cleanup() is called, it will call:
	meson_nfc_free_buffer(&meson_chip->nand);
	nand_cleanup(&meson_chip->nand);

nand_cleanup() in turn will call nand_detach() which calls the
.detach_chip() which is here meson_nand_detach_chip().

meson_nand_detach_chip() already calls meson_nfc_free_buffer(), so we
could double free some memory.

Fix it by removing the unneeded explicit call to meson_nfc_free_buffer().

Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
This patch is speculative, so review with care.
---
 drivers/mtd/nand/raw/meson_nand.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index ac3be92872d0..032180183339 100644
--- a/drivers/mtd/nand/raw/meson_nand.c
+++ b/drivers/mtd/nand/raw/meson_nand.c
@@ -1307,7 +1307,6 @@ static int meson_nfc_nand_chip_cleanup(struct meson_nfc *nfc)
 		if (ret)
 			return ret;
 
-		meson_nfc_free_buffer(&meson_chip->nand);
 		nand_cleanup(&meson_chip->nand);
 		list_del(&meson_chip->node);
 	}
-- 
2.34.1


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Re: [PATCH] mtd: rawnand: meson: Fix a potential double free issue

[Liang Yang]

Hi Christophe,

On 2022/5/21 0:41, Christophe JAILLET wrote:
> [ EXTERNAL EMAIL ]
> 
> When meson_nfc_nand_chip_cleanup() is called, it will call:
> 	meson_nfc_free_buffer(&meson_chip->nand);
> 	nand_cleanup(&meson_chip->nand);
> 
> nand_cleanup() in turn will call nand_detach() which calls the
> .detach_chip() which is here meson_nand_detach_chip().
> 
> meson_nand_detach_chip() already calls meson_nfc_free_buffer(), so we
> could double free some memory.
> 
> Fix it by removing the unneeded explicit call to meson_nfc_free_buffer().
> 
> Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> This patch is speculative, so review with care.
> ---
>   drivers/mtd/nand/raw/meson_nand.c | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
> index ac3be92872d0..032180183339 100644
> --- a/drivers/mtd/nand/raw/meson_nand.c
> +++ b/drivers/mtd/nand/raw/meson_nand.c
> @@ -1307,7 +1307,6 @@ static int meson_nfc_nand_chip_cleanup(struct meson_nfc *nfc)
>   		if (ret)
>   			return ret;
>   
> -		meson_nfc_free_buffer(&meson_chip->nand);
>   		nand_cleanup(&meson_chip->nand);
>   		list_del(&meson_chip->node);
>   	}

Acked-by: Liang Yang <liang.yang@amlogic.com>

Thanks,
Liang

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Re: [PATCH] mtd: rawnand: meson: Fix a potential double free issue

[Miquel Raynal]

On Fri, 2022-05-20 at 16:41:40 UTC, Christophe JAILLET wrote:
> When meson_nfc_nand_chip_cleanup() is called, it will call:
> 	meson_nfc_free_buffer(&meson_chip->nand);
> 	nand_cleanup(&meson_chip->nand);
> 
> nand_cleanup() in turn will call nand_detach() which calls the
> .detach_chip() which is here meson_nand_detach_chip().
> 
> meson_nand_detach_chip() already calls meson_nfc_free_buffer(), so we
> could double free some memory.
> 
> Fix it by removing the unneeded explicit call to meson_nfc_free_buffer().
> 
> Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> Acked-by: Liang Yang <liang.yang@amlogic.com>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next, thanks.

Miquel

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