On Wednesday, February 22, 2012 2:24:14 pm Konstantin Belousov wrote: > On Wed, Feb 22, 2012 at 11:29:40AM -0500, Rick Macklem wrote: > > Hiroki Sato wrote: > > > Hi, > > > > > > Just a report, but I got the following panic on an NFS server running > > > 8.3-PRERELEASE: > > > > > > ----(from here)---- > > > pool.allbsd.org dumped core - see /var/crash/vmcore.0 > > > > > > Tue Feb 21 10:59:44 JST 2012 > > > > > > FreeBSD pool.allbsd.org 8.3-PRERELEASE FreeBSD 8.3-PRERELEASE #7: Thu > > > Feb 16 19:29:19 JST 2012 h...@pool.allbsd.org:/usr/obj/usr/src/sys/POOL > > > amd64 > > > > > > panic: Assertion lock == sq->sq_lock failed at > > > /usr/src/sys/kern/subr_sleepqueue.c:335 > > > > > Oops, I didn't know that mixing msleep() and tsleep() calls on the same > > event wasn't allowed. > > There are two places in the code where it did a: > > mtx_unlock(); > > tsleep(); > > left over from the days when it was written for OpenBSD. > This sequence allows to lost the wakeup which is happen right after > cache unlock (together with clearing the RC_WANTED flag) but before > the thread enters sleep state. The tsleep has a timeout so thread should > recover in 10 seconds, but still. > > Anyway, you should use consistent outer lock for the same wchan, i.e. > no lock (tsleep) or mtx (msleep), but not mix them.
Correct. > > I don't think the mix would actually break anything, except that the > > MPASS() assertion fails, but I've cc'd jhb@ since he seems to have been > > the author of the sleep() stuff. > > > > Anyhow, please try the attached patch which replaces the mtx_unlock(); tsleep(); with > > msleep()s using PDROP. If the attachment gets lost, the patch is also here: > > http://people.freebsd.org/~rmacklem/tsleep.patch > > > > Thanks for reporting this, rick > > ps: Is mtx_lock() now preferred over msleep()? > What do you mean ? mtx_sleep() is preferred over msleep(), but I doubt I will remove msleep() anytime soon. -- John Baldwin _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
