On Fri, Jan 12, 2024 at 10:01 AM Jeffery Miller jefferymiller@google.com wrote:

For 5.15 attempting to use an ax88179_178a adapter "0b95:1790 ASIX Electronics Corp. AX88179 Gigabit Ethernet" started causing crashes. This did not reproduce in the 6.6 kernel.

Looks like my patch set was not fully backported. The patchset didn't have a "Fixes" tag, so it looks it was partially pulled for d63fafd6cc28 ("net: usb: ax88179_178a: avoid failed operations when device is disconnected") which does have a fixes tag. Just looks like a bad backport here. Apologies, I should have caught it when I saw the stable email, I didn't realize it was only for part of the changeset.

Thanks, Justin

The crashes were narrowed down to the following two commits brought into v5.15.146:

commit d63fafd6cc28 ("net: usb: ax88179_178a: avoid failed operations when device is disconnected") commit f860413aa00c ("net: usb: ax88179_178a: wol optimizations")

Those two use an uninitialized pointer `dev->driver_priv`.

In later kernels this pointer is initialized in commit 2bcbd3d8a7b4 ("net: usb: ax88179_178a: move priv to driver_priv").

Picking in the two following commits fixed the issue for me on 5.15: commit 9718f9ce5b86 ("net: usb: ax88179_178a: remove redundant init code") commit 2bcbd3d8a7b4 ("net: usb: ax88179_178a: move priv to driver_priv")

The commit 9718f9ce5b86 ("net: usb: ax88179_178a: remove redundant init code") was required for the fix to apply cleanly.