Re: [PATCH 6.1 000/102] 6.1.98-rc1 review

[Greg KH]

On Sun, Jul 14, 2024 at 06:05:25PM +0200, Salvatore Bonaccorso wrote:
> Hi,
> 
> On Sun, Jul 14, 2024 at 05:32:39PM +0200, Michał Pecio wrote:
> > This looks like bug 219039, please see if my suggested solution works.
> > 
> > The upstream commit is correct, because the call to inc_deq() has been
> > moved outside handle_tx_event() so there is no longer this critical
> > difference between doing 'goto cleanup' and 'return 0'. The intended
> > change of this commit also makes sense to me.
> > 
> > This refactor is already present in v6.9 so I don't think the commit
> > will have any effect besides fixing the isochronous bug which it is
> > meant to fix.
> > 
> > But it is not present in v6.6 and v6.1, so they break/crash/hang/etc.
> > Symptoms may vary, but I believe the root cause is the same because the
> > code is visibly wrong.
> > 
> > 
> > I would like to use this opportunity to point out that the xhci driver
> > is currenty undergoing (much needed IMO) cleanups and refactors and
> > this is not the first time when a naive, verbatim backport is attempted
> > of a patch which works fine on upstream, but causes problems on earlier
> > kernels. These things need special scrutiny, beyond just "CC:stable".
> 
> For tracking I guess this should go as well to the regressions list?
> 
> #regzbot introduced: 948554f1bb16e15b90006c109c3a558c66d4c4ac
> #regzbot title: freezes on plugging USB connector due to 948554f1bb16 ("usb: xhci: prevent potential failure in handle_tx_event() for Transfer events without TRB")
> #regzbot monitor: https://bugzilla.kernel.org/show_bug.cgi?id=219039
> 
> Thorsten I hope I got the most bits correctly, how would one inform
> regzbot about the regresssion for 6.1.98 and 6.6.39 but not happening
> in the upper versions?

I'll handle this and go release new kernels with just this reverted in
it.  Let my morning coffee kick in first...

thanks,

greg k-h