[PATCH net v2] tg3: prevent use of uninitialized remote_adv and local_adv variables

[PATCH net v2] tg3: prevent use of uninitialized remote_adv and local_adv variables

[Alexey Simakov]

Some execution paths that jump to the fiber_setup_done label
could leave the remote_adv and local_adv variables uninitialized
and then use it.

Initialize this variables at the point of definition to avoid this.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 85730a631f0c ("tg3: Add SGMII phy support for 5719/5718 serdes")
Co-developed-by: Alexandr Sapozhnikov <alsp705@gmail.com>
Signed-off-by: Alexandr Sapozhnikov <alsp705@gmail.com>
Signed-off-by: Alexey Simakov <bigalex934@gmail.com>
---

v2 - remove bogus lines with initialization of variables in function,
since its initialized at definition point now.

link to v1: https://lore.kernel.org/netdev/20251002091224.11-1-alsp705@gmail.com/

 drivers/net/ethernet/broadcom/tg3.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 7f00ec7fd7b9..d78cafdb2094 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -5803,7 +5803,7 @@ static int tg3_setup_fiber_mii_phy(struct tg3 *tp, bool force_reset)
 	u32 current_speed = SPEED_UNKNOWN;
 	u8 current_duplex = DUPLEX_UNKNOWN;
 	bool current_link_up = false;
-	u32 local_adv, remote_adv, sgsr;
+	u32 local_adv = 0, remote_adv = 0, sgsr;
 
 	if ((tg3_asic_rev(tp) == ASIC_REV_5719 ||
 	     tg3_asic_rev(tp) == ASIC_REV_5720) &&
@@ -5944,9 +5944,6 @@ static int tg3_setup_fiber_mii_phy(struct tg3 *tp, bool force_reset)
 		else
 			current_duplex = DUPLEX_HALF;
 
-		local_adv = 0;
-		remote_adv = 0;
-
 		if (bmcr & BMCR_ANENABLE) {
 			u32 common;
 
-- 
2.34.1

Re: [PATCH net v2] tg3: prevent use of uninitialized remote_adv and local_adv variables

[Pavan Chebbi]

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On Tue, Oct 14, 2025 at 10:18 PM Alexey Simakov <bigalex934@gmail.com> wrote:
>
> Some execution paths that jump to the fiber_setup_done label
> could leave the remote_adv and local_adv variables uninitialized
> and then use it.
>
> Initialize this variables at the point of definition to avoid this.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 85730a631f0c ("tg3: Add SGMII phy support for 5719/5718 serdes")
> Co-developed-by: Alexandr Sapozhnikov <alsp705@gmail.com>
> Signed-off-by: Alexandr Sapozhnikov <alsp705@gmail.com>
> Signed-off-by: Alexey Simakov <bigalex934@gmail.com>

LGTM.
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>

> ---
>
> v2 - remove bogus lines with initialization of variables in function,
> since its initialized at definition point now.
>
> link to v1: https://lore.kernel.org/netdev/20251002091224.11-1-alsp705@gmail.com/
>
>  drivers/net/ethernet/broadcom/tg3.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
> index 7f00ec7fd7b9..d78cafdb2094 100644
> --- a/drivers/net/ethernet/broadcom/tg3.c
> +++ b/drivers/net/ethernet/broadcom/tg3.c
> @@ -5803,7 +5803,7 @@ static int tg3_setup_fiber_mii_phy(struct tg3 *tp, bool force_reset)
>         u32 current_speed = SPEED_UNKNOWN;
>         u8 current_duplex = DUPLEX_UNKNOWN;
>         bool current_link_up = false;
> -       u32 local_adv, remote_adv, sgsr;
> +       u32 local_adv = 0, remote_adv = 0, sgsr;
>
>         if ((tg3_asic_rev(tp) == ASIC_REV_5719 ||
>              tg3_asic_rev(tp) == ASIC_REV_5720) &&
> @@ -5944,9 +5944,6 @@ static int tg3_setup_fiber_mii_phy(struct tg3 *tp, bool force_reset)
>                 else
>                         current_duplex = DUPLEX_HALF;
>
> -               local_adv = 0;
> -               remote_adv = 0;
> -
>                 if (bmcr & BMCR_ANENABLE) {
>                         u32 common;
>
> --
> 2.34.1

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Re: [PATCH net v2] tg3: prevent use of uninitialized remote_adv and local_adv variables

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 14 Oct 2025 19:47:38 +0300 you wrote:
> Some execution paths that jump to the fiber_setup_done label
> could leave the remote_adv and local_adv variables uninitialized
> and then use it.
> 
> Initialize this variables at the point of definition to avoid this.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> [...]

Here is the summary with links:
  - [net,v2] tg3: prevent use of uninitialized remote_adv and local_adv variables
    https://git.kernel.org/netdev/net/c/0c3f2e62815a

You are awesome, thank you!
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