On Fri, Dec 17, 2021 at 11:32:07AM +0100, Sebastian Andrzej Siewior wrote: > On 2021-12-15 16:44:12 [+0100], Florent Carli wrote: > > Hello all, > Hi, > … > > I tried to reproduce this but nothing. However… > > > If we try the experiment once again, the tap will fail but we won't > > get a new backtrace. > > The backtrace is meant to appear only once. > > > A first analyzis was done on the #linux-rt irc channel: > > "huh, looks like the underlying issue is hitting the WARN_ON_ONCE() > > condition in eventfd_signal(), but in the bug handler (which > > apparently is preemptible), we get into print_stop_info() and try to > > use smp_processor_id() in that context, which is wrong because thigns > > are preemptible. > > I can't see the smp_processor_id() usage in mainlin (I don't have an > > RT tree to hand), but someone with more RT knowledge might want to > > look at that" > > So that smp_processor_id() thingy is sad because the code changed before > it hit upstream and I didn't notice it. > Patch #1 contains the missing bits and avoids the backtrace from > WARN_ON_ONCE(). > Patch #2 is a backport from upstream avoiding trigger WARN_ON_ONCE in > the first place. > Could you please try these two if they help? Sebastian, I just released v5.10.87-rt59, so v5.10-rt is up to date with stable. Do you want me to work on a -rc release with the two patches for this thread or do you prefer I wait for Florent's answer? Best regards, Luis
