On 2017.09.05 at 10:53 +0200, Peter Zijlstra wrote: > On Tue, Sep 05, 2017 at 09:27:38AM +0200, Markus Trippelsdorf wrote: > > Current mainline git (24e700e291d52bd2) hangs when building software > > concurrently (for example perf). > > The issue is not 100% reproducible (sometimes building perf succeeds), > > so bisecting will not work. > > Sadly I cannot reproduce, I had: > > while :; do make clean; make; done > > running on tools/perf for a while, and now have: > > while :; do make O=defconfig-build clean; make O=defconfig-build -j80; done > > running, all smooth sailing, although there's the hope that the moment I > hit send on this email the box comes unstuck. > > > Magic SysRq key doesn't work and there is nothing in the logs. > > Enabling CONFIG_PROVE_LOCKING makes the issue go away. > > SysRq not working is suspicious.. and I take it the NMI watchdog also > isn't firing?
Yes. > > Any ideas on how to debug this further? > > So you have a (real) serial line on that box? Sadly, no. But hopefully somebody else (with a proper kernel debugging setup) will reproduce the issue soon. -- Markus
