[PATCH net] net: usb: lan78xx: fix error handling in lan78xx_open()

[PATCH net] net: usb: lan78xx: fix error handling in lan78xx_open()

[Stefano Munari]

A failed interrupt URB submission leaves NAPI enabled and EVENT_DEV_OPEN
set. A subsequent open enables NAPI again, triggering BUG_ON() in
napi_enable().

Clear EVENT_DEV_OPEN and disable NAPI on the submission error path.

Reproduced using failslab on a Raspberry Pi 3 Model B+ (LAN7515).
With the fix, the injected allocation failure returns -ENOMEM and a
subsequent open succeeds. Verified connectivity with ping and SSH.

Fixes: e110bc825897 ("net: usb: lan78xx: Convert to PHYLINK for improved PHY and MAC management")
Signed-off-by: Stefano Munari <stefanomunari.sm@gmail.com>
---
 drivers/net/usb/lan78xx.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 5655941f1478..6a95934bb3d3 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -3484,6 +3484,8 @@ static int lan78xx_open(struct net_device *net)
 		if (ret < 0) {
 			netif_err(dev, ifup, dev->net,
 				  "intr submit %d\n", ret);
+			clear_bit(EVENT_DEV_OPEN, &dev->flags);
+			napi_disable(&dev->napi);
 			goto done;
 		}
 	}
-- 
2.55.0

Re: [PATCH net] net: usb: lan78xx: fix error handling in lan78xx_open()

[sashiko-bot]

> A failed interrupt URB submission leaves NAPI enabled and EVENT_DEV_OPEN
> set. A subsequent open enables NAPI again, triggering BUG_ON() in
> napi_enable().
> 
> Clear EVENT_DEV_OPEN and disable NAPI on the submission error path.
> 
> Reproduced using failslab on a Raspberry Pi 3 Model B+ (LAN7515).
> With the fix, the injected allocation failure returns -ENOMEM and a
> subsequent open succeeds. Verified connectivity with ping and SSH.
> 
> Fixes: e110bc825897 ("net: usb: lan78xx: Convert to PHYLINK for improved PHY and MAC management")
> Signed-off-by: Stefano Munari <stefanomunari.sm@gmail.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261016000521.92868-1-stefanomunari.sm@gmail.com?part=1