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

["Pankaj Dubey" <pankaj.dubey@samsung.com>]

> -----Original Message-----
> From: Rob Herring (Arm) <robh@kernel.org>
> Sent: Tuesday, December 17, 2024 11:42 PM
> To: Lee Jones <lee@kernel.org>; Arnd Bergmann <arnd@arndb.de>; Pankaj
> Dubey <pankaj.dubey@samsung.com>; Heiko Stuebner <heiko@sntech.de>;
> Liviu Dudau <liviu.dudau@arm.com>; Sudeep Holla <sudeep.holla@arm.com>;
> Lorenzo Pieralisi <lpieralisi@kernel.org>
> Cc: Peter Griffin <peter.griffin@linaro.org>; Will McVicker
> <willmcvicker@google.com>; John Madieu <john.madieu.xa@bp.renesas.com>;
> Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>; linux-
> kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org
> Subject: [PATCH v2 1/3] mfd: syscon: Fix race in device_node_get_regmap()
> 
> 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@linaro.org>
> Tested-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
> ---

Tested on arm64: Tesla FSD 

Tested-by: Pankaj Dubey <pankaj.dubey@samsung.com>

Thanks.
Pankaj Dubey