Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 23 Nov 2018 12:02:55 +0100 | From | Andrea Parri <> | Subject | Re: [PATCH v2] kmemleak: Turn kmemleak_lock to raw spinlock on RT |
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> is this an RT-only problem? Because mainline should not allow read->read > locking or read->write locking for reader-writer locks. If this only > happens on v4.18 and not on v4.19 then something must have fixed it.
Probably misunderstanding, but I'd say that read->read locking is "the norm"...?
If you don't use qrwlock, readers are also "recursive", in part.,
P0 P1 read_lock(l) write_lock(l) read_lock(l)
won't block P0 on the second read_lock(). (qrwlock somehow complicate the analysis; IIUC, they are recursive if and only if in_interrupt().).
Andrea
> > > Sebastian
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