On Thu, Jun 27, 2019 at 1:43 PM Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> wrote: > > On Thu, Jun 27, 2019 at 11:40 AM Sebastian Andrzej Siewior > <bigeasy@xxxxxxxxxxxxx> wrote: > > > > On 2019-06-27 11:37:10 [-0400], Joel Fernandes wrote: > > > Sebastian it would be nice if possible to trace where the > > > t->rcu_read_unlock_special is set for this scenario of calling > > > rcu_read_unlock_special, to give a clear idea about whether it was > > > really because of an IPI. I guess we could also add additional RCU > > > debug fields to task_struct (just for debugging) to see where there > > > unlock_special is set. > > > > > > Is there a test to reproduce this, or do I just boot an intel x86_64 > > > machine with "threadirqs" and run into it? > > > > Do you want to send me a patch or should I send you my kvm image which > > triggers the bug on boot? > > I could reproduce this as well just booting Linus tree with threadirqs > command line and running rcutorture. In 15 seconds or so it locks > up... gdb backtrace shows the recursive lock: Sorry that got badly wrapped, so I pasted it here: https://hastebin.com/ajivofomik.shell
