Re: [PATCH v2 1/3] mfd: syscon: Fix race in device_node_get_regmap()

[William McVicker]

On 12/17/2024, Rob Herring (Arm) wrote:
> It is possible for multiple, simultaneous callers calling
> device_node_get_regmap() with the same node to fail to find an entry in
> the syscon_list. There is a period of time while the first caller is
> calling of_syscon_register() that subsequent callers also fail to find
> an entry in the syscon_list and then call of_syscon_register() a second
> time.
> 
> Fix this by keeping the lock held until after of_syscon_register()
> completes and adds the node to syscon_list. Convert the spinlock to a
> mutex as many of the functions called in of_syscon_register() such as
> kzalloc() and of_clk_get() may sleep.
> 
> Fixes: bdb0066df96e ("mfd: syscon: Decouple syscon interface from platform devices")
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> Tested-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> Signed-off-by: Rob Herring (Arm) <robh@xxxxxxxxxx>

I verified this works on my Pixel 6. Thanks!

Tested-by: Will McVicker <willmcvicker@xxxxxxxxxx>

Thanks,
Will