On Tue, Jul 21, 2020 at 01:29:08PM +0200, Pavel Machek wrote:
Hi!
After some investigations, we concluded the following:
- the issue does not exist in vanilla v5.8-rc4+
- [bisecting shows that] the panic on v4.14.186 is caused by the lack of v5.6-rc1 commit 987351e1ea7772 ("phy: core: Add consumer device link support"). Getting evidence for that is easy. Reverting 987351e1ea7772 in vanilla leads to a similar backtrace [2].
Questions:
- Backporting 987351e1ea7772 ("phy: core: Add consumer device link support") to v4.14.187 looks challenging enough, so probably not worth it. Anybody to contradict this?
I'm not sure about v4.14.187, but backport to v4.19 is quite simple (just ignore single non-existing file) and passes basic testing.
Would that be better solution for 4.19 and newer?
If Eugeniu could confirm that doing so on 4.19+ works for him, sure.
He did:
Message-ID: 20200721065054.GA8290@lxhi-065.adit-jv.com Technically yes. Backporting 987351e1ea7772 to v4.19.x avoids the panic. ... FWIW I confirm that:
- setup [A] leads to the issue reported in [C]
- setup [B] resolves the issue reported in [C]
[A] v4.19 + 16bdc04cc98 + 1cb3b0095c3 + 79112cc3c29f [B] v4.19 + 16bdc04cc98 + 1cb3b0095c3 + 79112cc3c29f + 987351e1ea7 [C] https://lore.kernel.org/linux-usb/20200709070023.GA18414@lxhi-065.adit-jv.co...
Awesome, I can queue it back for the next release.