On Wed, Nov 23, 2022 at 11:06:48PM +0100, Frederic Weisbecker wrote: > On Wed, Nov 23, 2022 at 11:45:50PM +0800, Pengfei Xu wrote: > > On 2022-11-23 at 15:37:58 +0100, Frederic Weisbecker wrote: > > > I have no idea how to solve the situation without violating the pid_namespace > > > rules and unshare() semantics (although I wish unshare(CLONE_NEWPID) had a less > > > error prone behaviour with allowing creating more than one task belonging to the > > > same namespace). > > > > > > So probably having an SRCU read side critical section within exit_notify() is > > > not a good idea, is there a solution to work around that for rcu tasks? > > > > > Thanks for the analysis! > > Add one more information: I tried to revert this commit only on top of > > v6.1-rc5 mainline by script, but it caused kernel make to fail, it could not > > confirm the bisect information is 100% accurate if I could not pass the > > revert step verification. I just provide all the information I could. > > No problem, I managed to reproduce with latest upstream. > I don't think the bisected commit is the culprit though, it may perhaps just make > the issue more likely to happen. Frederic, Boqun, Neeraj, and I dug through this earlier today, and record of our wanderings may be found here: https://docs.google.com/document/d/1hJxgiZ5TMZ4YJkdJPLAkRvq7sYQ-A7svgA8no6i-v8k/edit?usp=sharing It looks like we can break the deadlock within RCU Tasks, but it also looks like the namespace-PID semantics are at best an accident waiting to happen. ;-) Thanx, Paul > Thanks. > > > > > And this issue is too difficult to me. > > If I find more clue, I will update the eamil. > > > > Thanks! > > BR. > > > > > Thanks.
