Hello Johannes, > -----Original Message----- > From: Berg, Johannes <johannes.berg@xxxxxxxxx> > Sent: Monday, December 4, 2023 11:41 PM > To: Borah, Chaitanya Kumar <chaitanya.kumar.borah@xxxxxxxxx> > Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Kurmi, Suresh Kumar > <suresh.kumar.kurmi@xxxxxxxxx>; Saarinen, Jani <jani.saarinen@xxxxxxxxx> > Subject: RE: Regression on linux-next (next-20231130) > > Hi, > > > [snip lockdep report] > > > commit f4acfcd4deb158b96595250cc332901b282d15b0 > > Author: Johannes Berg johannes.berg@xxxxxxxxx > > Date: Fri Nov 24 17:25:25 2023 +0100 > > > > debugfs: annotate debugfs handlers vs. removal with lockdep > > Yes, obviously, since before that there was no lockdep class > "debugfs:i915_pipe" 😊 > > > We also verified that if we revert the patch the issue is not seen. > > > > Could you please check why the patch causes this regression and > > provide a fix if necessary? > > First off, I already sent a revert, which should be included in the next -rc. > Anyway this patch shouldn't have been included in the -rc cycle, I just > erroneously included it with some bugfixes (that patch-wise had a > dependency). > > Secondly, we did find a false positive in another case, and yours seems to be > the same or similar, due to seq_file not differentiating between the file > instances. > > That's a bit unfortunate, because we _did_ have actual deadlocks in wireless > with debugfs_remove() being called on a file while holding a lock that the file > also acquires, which can lead to a deadlock. Unless we differentiate seq_file > instances though, there doesn't seem to be a good way to annotate that in > debugfs, as this report and others show. Thank you for the confirmation. We will wait for the revert to be included in linux-next. Sounds like a useful addition. Hopefully, we can find a way for both of them to co-exist. Regards Chaitanya > > johannes > --
