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[2001:470:1f08:1f7::2]) by smtp.gmail.com with ESMTPSA id p17sm3252084pfi.97.2017.02.11.00.19.30 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Sat, 11 Feb 2017 00:19:32 -0800 (PST) Date: Sat, 11 Feb 2017 09:19:24 +0100 From: Mateusz Guzik To: Ben Woods Cc: FreeBSD Current Subject: Re: Kernel crashes from turnstile_broadcast (/usr/src/sys/kern/subr_turnstile.c:837) Message-ID: <20170211081924.GA3868@dft-labs.eu> Mail-Followup-To: Mateusz Guzik , Ben Woods , FreeBSD Current References: <20160922130141.GA9643@dft-labs.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 11 Feb 2017 08:19:34 -0000 On Thu, Oct 27, 2016 at 09:09:16PM +0800, Ben Woods wrote: > On 24 September 2016 at 18:13, Ben Woods wrote: > > > On 22 September 2016 at 21:01, Mateusz Guzik wrote: > > > >> On Thu, Sep 22, 2016 at 08:48:29PM +0800, Ben Woods wrote: > >> > #13 0xffffffff80b4d91c in turnstile_broadcast (ts=0x0, queue=1) at > >> > /usr/src/sys/kern/subr_turnstile.c:837 > >> > #14 0xffffffff80ae5e1f in __rw_wunlock_hard (c=0xfffff803f886d960, > >> > tid=, file=, line= >> > optimized out>) > >> > at /usr/src/sys/kern/kern_rwlock.c:1027 > >> > >> can you please: > >> f 14 > >> x/xg c > >> > >> > >> -- > >> Mateusz Guzik > >> > > > > Thanks for the help Mateusz. > > > > (kgdb) f 14 > > #14 0xffffffff80ae5e1f in __rw_wunlock_hard (c=0xfffff803f886d960, > > tid=, file=, line= > optimized out>) > > at /usr/src/sys/kern/kern_rwlock.c:1027 > > 1027 turnstile_broadcast(ts, queue); > > Current language: auto; currently minimal > > (kgdb) x/xg c > > 0xfffff803f886d960: 0xfffff8032893aa00 > > > > Regards, > > Ben > > > > Hi everyone, > > Just a heads up that after updating my FreeBSD 12-current machine to > r307773 I am still getting this kernel panic. > > Note that I have compiled the kernel with VIMAGE support if that makes any > difference. > > Mateusz: any further ideas on what it could be? > > Any help is appreciated :) > long time no see Is the problem still happening? There were quite a few locking changes recently and they could have interferred with the bug, so to speak. Can you move your kernel to r313260 (which predates locking changes) and make sure it is still there? The thread value shown in your first message corresponds to the lock value seen in __rw_wunlock_hard. But we should not get there if that's the case so there is something fishy going on. If the bug is still there at r313260, I'll provide you with a debug patch which will tell us what value was found and prevented a clean unlock. Then we will see if perhaps there are transient flags set or something corrupts the value somehow. -- Mateusz Guzik