[PATCH net] net: phy: fix phy_read_poll_timeout argument type in genphy_loopback

[PATCH net] net: phy: fix phy_read_poll_timeout argument type in genphy_loopback

[Nikita Kiryushin]

read_poll_timeout inside phy_read_poll_timeout can set val negative
in some cases (for example, __mdiobus_read inside phy_read can return
-EOPNOTSUPP).

Supposedly, commit 4ec732951702 ("net: phylib: fix phy_read*_poll_timeout()")
should fix problems with wrong-signed vals, but I do not see how
as val is sent to phy_read as is and __val = phy_read (not val)
is checked for sign.

Change val type for signed to allow better error handling as done in other
phy_read_poll_timeout callers. This will not fix any error handling
by itself, but allows, for example, to modify cond with appropriate
sign check or check resulting val separately.

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

Fixes: 014068dcb5b1 ("net: phy: genphy_loopback: add link speed configuration")
Signed-off-by: Nikita Kiryushin <kiryushin@ancud.ru>
---
  drivers/net/phy/phy_device.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 8297ef681bf5..6c6ec9475709 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -2831,8 +2831,8 @@ EXPORT_SYMBOL(genphy_resume);
  int genphy_loopback(struct phy_device *phydev, bool enable)
  {
  	if (enable) {
-		u16 val, ctl = BMCR_LOOPBACK;
-		int ret;
+		u16 ctl = BMCR_LOOPBACK;
+		int ret, val;
  
  		ctl |= mii_bmcr_encode_fixed(phydev->speed, phydev->duplex);
  
-- 
2.34.1

Re: [PATCH net] net: phy: fix phy_read_poll_timeout argument type in genphy_loopback

[Jakub Kicinski]

On Thu, 14 Mar 2024 14:15:37 +0300 Nikita Kiryushin wrote:
> read_poll_timeout inside phy_read_poll_timeout can set val negative
> in some cases (for example, __mdiobus_read inside phy_read can return
> -EOPNOTSUPP).
> 
> Supposedly, commit 4ec732951702 ("net: phylib: fix phy_read*_poll_timeout()")
> should fix problems with wrong-signed vals, but I do not see how
> as val is sent to phy_read as is and __val = phy_read (not val)
> is checked for sign.
> 
> Change val type for signed to allow better error handling as done in other
> phy_read_poll_timeout callers. This will not fix any error handling
> by itself, but allows, for example, to modify cond with appropriate
> sign check or check resulting val separately.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 014068dcb5b1 ("net: phy: genphy_loopback: add link speed configuration")
> Signed-off-by: Nikita Kiryushin <kiryushin@ancud.ru>

Please use git send email, the patch is mangled.
-- 
pw-bot: cr

[PATCH net] net: phy: fix phy_read_poll_timeout argument type in genphy_loopback

[Nikita Kiryushin]

read_poll_timeout inside phy_read_poll_timeout can set val negative
in some cases (for example, __mdiobus_read inside phy_read can return
-EOPNOTSUPP).

Supposedly, commit 4ec732951702 ("net: phylib: fix phy_read*_poll_timeout()")
should fix problems with wrong-signed vals, but I do not see how
as val is sent to phy_read as is and __val = phy_read (not val)
is checked for sign.

Change val type for signed to allow better error handling as done in other
phy_read_poll_timeout callers. This will not fix any error handling
by itself, but allows, for example, to modify cond with appropriate
sign check or check resulting val separately.

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

Fixes: 014068dcb5b1 ("net: phy: genphy_loopback: add link speed configuration")
Signed-off-by: Nikita Kiryushin <kiryushin@ancud.ru>
---
 drivers/net/phy/phy_device.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 8297ef681bf5..6c6ec9475709 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -2831,8 +2831,8 @@ EXPORT_SYMBOL(genphy_resume);
 int genphy_loopback(struct phy_device *phydev, bool enable)
 {
 	if (enable) {
-		u16 val, ctl = BMCR_LOOPBACK;
-		int ret;
+		u16 ctl = BMCR_LOOPBACK;
+		int ret, val;
 
 		ctl |= mii_bmcr_encode_fixed(phydev->speed, phydev->duplex);
 
-- 
2.34.1

Re: [PATCH net] net: phy: fix phy_read_poll_timeout argument type in genphy_loopback

[Russell King (Oracle)]

On Fri, Mar 15, 2024 at 08:50:52PM +0300, Nikita Kiryushin wrote:
> read_poll_timeout inside phy_read_poll_timeout can set val negative
> in some cases (for example, __mdiobus_read inside phy_read can return
> -EOPNOTSUPP).
> 
> Supposedly, commit 4ec732951702 ("net: phylib: fix phy_read*_poll_timeout()")
> should fix problems with wrong-signed vals, but I do not see how
> as val is sent to phy_read as is and __val = phy_read (not val)
> is checked for sign.
> 
> Change val type for signed to allow better error handling as done in other
> phy_read_poll_timeout callers. This will not fix any error handling
> by itself, but allows, for example, to modify cond with appropriate
> sign check or check resulting val separately.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 014068dcb5b1 ("net: phy: genphy_loopback: add link speed configuration")
> Signed-off-by: Nikita Kiryushin <kiryushin@ancud.ru>

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Thanks!

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Re: [PATCH net] net: phy: fix phy_read_poll_timeout argument type in genphy_loopback

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Fri, 15 Mar 2024 20:50:52 +0300 you wrote:
> read_poll_timeout inside phy_read_poll_timeout can set val negative
> in some cases (for example, __mdiobus_read inside phy_read can return
> -EOPNOTSUPP).
> 
> Supposedly, commit 4ec732951702 ("net: phylib: fix phy_read*_poll_timeout()")
> should fix problems with wrong-signed vals, but I do not see how
> as val is sent to phy_read as is and __val = phy_read (not val)
> is checked for sign.
> 
> [...]

Here is the summary with links:
  - [net] net: phy: fix phy_read_poll_timeout argument type in genphy_loopback
    https://git.kernel.org/netdev/net/c/32fa4366cc4d

You are awesome, thank you!
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