Messages in this thread | | | Date | Mon, 5 May 2014 20:08:02 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [3.15-rc3] rtmutex-debug assertion. |
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B1;3202;0cOn Fri, 2 May 2014, Dave Jones wrote: > On Wed, Apr 30, 2014 at 11:13:57AM +0200, Thomas Gleixner wrote: > > On Tue, 29 Apr 2014, Dave Jones wrote: > > > This is trickier to reproduce than it first seemed, as logging slows > > > things down so much. But after a few hours, it logged that the > > > call that triggered this was.. > > > > > > futex(uaddr=0x7f55ff8c4000, op=0x6, val=0x200000006223800b, utime=0x7f55ff8c4000, uaddr2=0x7f55ff8c4000, val3=-123) > > > > > > Those addresses come from an mmap we made on startup.. > > > > > > [init] mapping[3]: (zeropage PROT_READ | PROT_WRITE) 0x7f55ff8c4000 (1MB) > > > > > > op = FUTEX_LOCK_PI > > > > > > val seems to be garbage. > > > > > > I'll do another run, just to see if it's always the same set of values, > > > but it's going to probably take an overnight run. > > > > Do you have the full fuzzing log, so I can see what happened > > before/around that? > > This is tough, because it takes a long time to reproduce when the > logging is enabled, and that ends up generating a lot of output. > I've tried to cut it down some using just 4 threads, but that's > still over 30M of logs. > http://www.codemonkey.org.uk/junk/futex.tar.xz > > In this run, child0 was the pid that faulted. > You can see the last line in trinity-child0.log has a similar > fingerprint to the trace above. > > One thing that does look suspicious, is that all 4 threads were doing > op=0x6 right before the kernel went south. > > Hope this helps.
I twisted my brain around that for a fricking long time, but I really can't see the failure in the code.
Neither did I succeed to trigger the issue in a VM (with and without function tracing) on Linus latest.
I grabbed trinity source and did:
# ./trinity -l off -c futex -q
That should be enough, right?
All I see in dmesg are occasional ooms which kill random trinity childs.
I ran that stuff for almost two days now with a total of 629656086 syscalls. :(
Thanks,
tglx
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