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[0/2] mtd: spi-nor: Fix unbind deadlock and use-after-free

Message ID cover.1788404586.git.tze.yee.ng@altera.com
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Series mtd: spi-nor: Fix unbind deadlock and use-after-free | expand

Message

NG, TZE YEE Sept. 3, 2026, 3:14 a.m. UTC 
From: Tze Yee Ng <tze.yee.ng@altera.com>

Two fixes in the spi-nor core around locking and driver unbind:

Patch 1 fixes a self-deadlock in spi_nor_rww_start_exclusive(), which
took nor->lock while its end helper re-acquired it via guard(mutex).

Patch 2 fixes a use-after-free where a sysfs unbind frees the
devm-allocated spi_nor while /dev/mtdX is still open. Give it a kref
lifetime on the spi-mem probe path and fail operations with -ENODEV
after unbind. Legacy controllers are unchanged.

Tze Yee Ng (2):
  mtd: spi-nor: Fix deadlock in spi_nor_rww_start_exclusive()
  mtd: spi-nor: core: Fix use-after-free of spi_nor on unbind with open
    handles

 drivers/mtd/spi-nor/core.c  | 113 ++++++++++++++++++++++++++++++++----
 include/linux/mtd/spi-nor.h |  17 ++++++
 2 files changed, 119 insertions(+), 11 deletions(-)

Comments

NG, TZE YEE Sept. 21, 2026, 6:35 a.m. UTC | #1 
On 21/9/2026 2:27 pm, NG, TZE YEE wrote:
> 
> *From:* NG, TZE YEE
> *Sent:* Thursday, September 3, 2026 11:14 AM
> *To:* Pratyush Yadav <pratyush@kernel.org>; Michael Walle 
> <mwalle@kernel.org>; Takahiro Kuwano <takahiro.kuwano@infineon.com>; 
> Tudor Ambarus <tudor.ambarus@linaro.org>; linux-mtd@lists.infradead.org 
> <linux-mtd@lists.infradead.org>; linux-kernel@vger.kernel.org <linux- 
> kernel@vger.kernel.org>
> *Subject:* [PATCH 0/2] mtd: spi-nor: Fix unbind deadlock and use-after-free
> From: Tze Yee Ng <tze.yee.ng@altera.com>
> 
> Two fixes in the spi-nor core around locking and driver unbind:
> 
> Patch 1 fixes a self-deadlock in spi_nor_rww_start_exclusive(), which
> took nor->lock while its end helper re-acquired it via guard(mutex).
> 
> Patch 2 fixes a use-after-free where a sysfs unbind frees the
> devm-allocated spi_nor while /dev/mtdX is still open. Give it a kref
> lifetime on the spi-mem probe path and fail operations with -ENODEV
> after unbind. Legacy controllers are unchanged.
> 
> Tze Yee Ng (2):
>    mtd: spi-nor: Fix deadlock in spi_nor_rww_start_exclusive()
>    mtd: spi-nor: core: Fix use-after-free of spi_nor on unbind with open
>      handles
> 
>   drivers/mtd/spi-nor/core.c  | 113 ++++++++++++++++++++++++++++++++----
>   include/linux/mtd/spi-nor.h |  17 ++++++
>   2 files changed, 119 insertions(+), 11 deletions(-)
> 
> -- 
> 2.43.7
> 

Hi,

Gentle ping on this patch. It has been over 2 weeks with no feedback.

Happy to address any review comments.

Thanks,
Tze Yee