RE: [Intel-wired-lan] [PATCH v2] ice: Fix improper handling of refcount in ice_dpll_init_rclk_pins()

[Pucha, HimasekharX Reddy]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of Gui-Dong Han
> Sent: Tuesday, September 3, 2024 5:19 PM
> To: Nguyen, Anthony L <anthony.l.nguyen@xxxxxxxxx>; Kitszel, Przemyslaw <przemyslaw.kitszel@xxxxxxxxx>; davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx
> Cc: netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx; Gui-Dong Han <hanguidong02@xxxxxxxxxxx>; baijiaju1990@xxxxxxxxx; intel-wired-lan@xxxxxxxxxxxxxxxx
> Subject: [Intel-wired-lan] [PATCH v2] ice: Fix improper handling of refcount in ice_dpll_init_rclk_pins()
>
> This patch addresses a reference count handling issue in the
> ice_dpll_init_rclk_pins() function. The function calls ice_dpll_get_pins(), which increments the reference count of the relevant resources. However, if the condition WARN_ON((!vsi || !vsi->netdev)) is met, the function currently returns an error without properly releasing the > resources acquired by ice_dpll_get_pins(), leading to a reference count leak.
>
> To resolve this, the check has been moved to the top of the function. This ensures that the function verifies the state before any resources are acquired, avoiding the need for additional resource management in the error path. 
>
> This bug was identified by an experimental static analysis tool developed by our team. The tool specializes in analyzing reference count operations and detecting potential issues where resources are not properly managed.
> In this case, the tool flagged the missing release operation as a potential problem, which led to the development of this patch.
>
> Fixes: d7999f5ea64b ("ice: implement dpll interface to control cgu")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Gui-Dong Han <hanguidong02@xxxxxxxxxxx>
> ---
> v2:
> * In this patch v2, the check for vsi and vsi->netdev has been moved to the top of the function to simplify error handling and avoid the need for resource unwinding.
>   Thanks to Simon Horman for suggesting this improvement.
> ---
>  drivers/net/ethernet/intel/ice/ice_dpll.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>

Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@xxxxxxxxx> (A Contingent worker at Intel)