On 01.07.24 16:34, Markus Schneider-Pargmann wrote: > On Mon, Jul 01, 2024 at 02:12:55PM GMT, Linux regression tracking (Thorsten Leemhuis) wrote: >> [CCing the regression list, as it should be in the loop for regressions: >> https://docs.kernel.org/admin-guide/reporting-regressions.html] >> >> Hi, Thorsten here, the Linux kernel's regression tracker. Top-posting >> for once, to make this easily accessible to everyone. >> >> Hmm, looks like there was not even a single reply to below regression >> report. But also seens Markus hasn't posted anything archived on Lore >> since about three weeks now, so he might be on vacation. >> >> Marc, do you might have an idea what's wrong with the culprit? Or do we >> expected Markus to be back in action soon? > > Great, ping here. Thx for replying! > @Matthias: Thanks for debugging and sorry for breaking it. If you have a > fix for this, let me know. I have a lot of work right now, so I am not > sure when I will have a proper fix ready. But it is on my todo list. Thx. This made me wonder: is "revert the culprit to resolve this quickly and reapply it later together with a fix" something that we should consider if a proper fix takes some time? Or is this not worth it in this case or extremely hard? Or would it cause a regression on it's own for users of 6.9? Ciao, Thorsten >> On 18.06.24 18:12, Matthias Schiffer wrote: >>> Hi Markus, >>> >>> we've found that recent kernels hang on the TI AM62x SoC (where no m_can interrupt is available and >>> thus the polling timer is used), always a few seconds after the CAN interfaces are set up. >>> >>> I have bisected the issue to commit a163c5761019b ("can: m_can: Start/Cancel polling timer together >>> with interrupts"). Both master and 6.6 stable (which received a backport of the commit) are >>> affected. On 6.6 the commit is easy to revert, but on master a lot has happened on top of that >>> change. >>> >>> As far as I can tell, the reason is that hrtimer_cancel() tries to cancel the timer synchronously, >>> which will deadlock when called from the hrtimer callback itself (hrtimer_callback -> m_can_isr -> >>> m_can_disable_all_interrupts -> hrtimer_cancel). >>> >>> I can try to come up with a fix, but I think you are much more familiar with the driver code. Please >>> let me know if you need any more information. >>> >>> Best regards, >>> Matthias >>> >>> > >
