On Thu, Oct 12, 2023 at 11:55:46AM +0200, J. Hannken-Illjes wrote: > > On 10. Oct 2023, at 20:58, Andrew Doran <a...@netbsd.org> wrote: > > > > On Tue, Oct 10, 2023 at 06:00:57PM +0200, J. Hannken-Illjes wrote: > > > >>> cvs rdiff -u -r1.63 -r1.64 src/sys/kern/sys_select.c > >> > >> - sleepq_unsleep(l, false); > >> + sleepq_remove(l->l_sleepq, l, true); > >> } > >> } > >> mutex_spin_exit(lock); > >> > >> Looks like sleepq_remove() unlocks l->l_mutex == lock and > >> then mutex_spin_exit(lock) will unlock an unlocked mutex. > > > > lock is held before the call to sleepq_remove() and this is also true at the > > time: l->l_mutex == lock. > > > > After the call lock is still held, but now l->l_mutex != lock, because l has > > changed state (e.g LSSLEEP -> LSRUN) which causes l_mutex to change in > > concert. There is a rough overview here: > > > > https://nxr.netbsd.org/xref/src/sys/kern/kern_lwp.c#156 > > > > Did you encounter a problem? > > This is not true for RUMP. Hero you added sleepq_remove() as > "sleepq_unsleep(l, true)". This will unlock l_mutex without changing. > > Just poking around and using sleepq_unsleep(l, false) here makes the > NFS tests using rump_server pass.
Ah, now I see, thank you. I committed a fix and will do a test run once my build completes. Cheers, Andrew
