diff mbox series

[v2] ice: Fix improper handling of refcount in ice_dpll_init_rclk_pins()

Message ID SY8P300MB0460F0F4B5D0BC6768DCA466C0932@SY8P300MB0460.AUSP300.PROD.OUTLOOK.COM (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series [v2] ice: Fix improper handling of refcount in ice_dpll_init_rclk_pins() | expand

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Context Check Description
netdev/series_format warning Single patches do not need cover letters; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 16 this patch: 16
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers fail 4 blamed authors not CCed: arkadiusz.kubalewski@intel.com jiri@resnulli.us michal.michalik@intel.com vadim.fedorenko@linux.dev; 4 maintainers not CCed: arkadiusz.kubalewski@intel.com jiri@resnulli.us michal.michalik@intel.com vadim.fedorenko@linux.dev
netdev/build_clang success Errors and warnings before: 16 this patch: 16
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 16 this patch: 16
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 16 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest fail net-next-2024-09-03--18-00 (tests: 714)

Commit Message

Gui-Dong Han Sept. 3, 2024, 11:48 a.m. UTC
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@vger.kernel.org
Signed-off-by: Gui-Dong Han <hanguidong02@outlook.com>
---
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(-)

Comments

Simon Horman Sept. 6, 2024, 8:18 a.m. UTC | #1
On Tue, Sep 03, 2024 at 11:48:43AM +0000, Gui-Dong Han wrote:
> 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@vger.kernel.org
> Signed-off-by: Gui-Dong Han <hanguidong02@outlook.com>
> ---
> 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.

Thanks for the update,

I agree with your analysis and that the problem is introduced by
the cited commit.

Reviewed-by: Simon Horman <horms@kernel.org>
Pucha, HimasekharX Reddy Sept. 11, 2024, 4:54 p.m. UTC | #2
> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of Gui-Dong Han
> Sent: Tuesday, September 3, 2024 5:19 PM
> To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel, Przemyslaw <przemyslaw.kitszel@intel.com>; davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com
> Cc: netdev@vger.kernel.org; linux-kernel@vger.kernel.org; stable@vger.kernel.org; Gui-Dong Han <hanguidong02@outlook.com>; baijiaju1990@gmail.com; intel-wired-lan@lists.osuosl.org
> 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@vger.kernel.org
> Signed-off-by: Gui-Dong Han <hanguidong02@outlook.com>
> ---
> 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@intel.com> (A Contingent worker at Intel)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/ice/ice_dpll.c b/drivers/net/ethernet/intel/ice/ice_dpll.c
index e92be6f130a3..b403d55303b8 100644
--- a/drivers/net/ethernet/intel/ice/ice_dpll.c
+++ b/drivers/net/ethernet/intel/ice/ice_dpll.c
@@ -1626,6 +1626,8 @@  ice_dpll_init_rclk_pins(struct ice_pf *pf, struct ice_dpll_pin *pin,
 	struct dpll_pin *parent;
 	int ret, i;
 
+	if (WARN_ON((!vsi || !vsi->netdev)))
+		return -EINVAL;
 	ret = ice_dpll_get_pins(pf, pin, start_idx, ICE_DPLL_RCLK_NUM_PER_PF,
 				pf->dplls.clock_id);
 	if (ret)
@@ -1641,8 +1643,6 @@  ice_dpll_init_rclk_pins(struct ice_pf *pf, struct ice_dpll_pin *pin,
 		if (ret)
 			goto unregister_pins;
 	}
-	if (WARN_ON((!vsi || !vsi->netdev)))
-		return -EINVAL;
 	dpll_netdev_pin_set(vsi->netdev, pf->dplls.rclk.pin);
 
 	return 0;