Re: [PATCH] clk: Fix referring to wrong pointer in devm_clk_release()

[Uwe Kleine-König]

Hello,

On Thu, Jun 23, 2022 at 10:02:22AM +0900, Kunihiko Hayashi wrote:
> At bind phase, __devm_clk_get() calls devres_alloc() to allocate devres,
> and dr->data is treated as a variable "state".
> 
> At unbind phase, release_nodes() calls devm_clk_release() specified by
> devres_alloc().
> 
> The argument "res" of devm_clk_release() is dr->data, and this entity is
> "state", however in devm_clk_release(), "*res" is treated as "state",
> resulting in pointer inconsistency.
> 
> Unbinding a driver caused a panic.
> 
>     Unable to handle kernel execute from non-executable memory
>     at virtual address ffff000100236810
>     ...
>     pc : 0xffff000100236810
>     lr : devm_clk_release+0x6c/0x9c
>     ...
>     Call trace:
>      0xffff000100236810
>      release_nodes+0xb0/0x150
>      devres_release_all+0x94/0xf8
>      device_unbind_cleanup+0x20/0x70
>      device_release_driver_internal+0x114/0x1a0
>      device_driver_detach+0x20/0x30
> 
> Cc: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> Fixes: abae8e57e49a ("clk: generalize devm_clk_get() a bit")
> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>

This is already fixed in clk-next:

	https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git/commit/?h=clk-next&id=8b3d743fc9e2542822826890b482afabf0e7522a

Thanks anyhow,
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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