Messages in this thread | | | From | Joel Fernandes <> | Date | Fri, 14 May 2021 10:52:31 -0400 | Subject | Silencing false lockdep warning related to seq lock |
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Hi Boqun, You might have worked on such issues so I thought you're a good person to ask.
After apply Laurent's SPF patchset [1] , we're facing a large number of (seemingly false positive) lockdep reports which are related to circular dependencies with seq locks.
lock(A); write_seqcount(B) vs. write_seqcount(B); lock(A)
This cannot deadlock obviously. My current strategy which I hate is to make it a raw seqcount write which bypasses lockdep. That's horrible for obvious reasons. Do you have any tricks/patches up your sleeve to silence these?
I suppose we still want to catch lockdep issues of the form (which peterz chatted to me about):
lock(A); write_seqcount(B) vs. read_seqcount(B); lock(A)
which seems like it can deadlock.
I would rather make lockdep useful to catch these and not miss out on them. Let me know what you think?
Cheers, -Joel
[1] https://lkml.org/lkml/2019/4/16/615
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