Re: rcu_prempt stalls / lockup

[Dave Jones <davej@redhat.com>]

On Thu, Apr 03, 2014 at 01:46:56PM -0700, Paul E. McKenney wrote:
 > So, how about reverting each commit in the RCU series, and then bisecting
 > through the reverts?  Something like the following:
 > 
 > 	wherever=linus/master # or substitute whatever point you wish.
 > 	# Create a revert branch for the rcu.2014.02.26a branch
 > 	git checkout -b anti-fixes $wherever
 > 	git revert 5cb5c6e18f822b19bd41a2c0f9930c82b3ec0bc9
 > 	git revert 7a754743185a4b05818e10058fa2fbe4e6969085
 > 	git revert 8857563b819b140aa8c9be920cfe44d5d3f808b7
 > 	git revert add1f0995454374d90c9d6b2c420d2fba3d0a4e3
 > 	git revert ae1670339c95c3ff96ab10582506cf827c5fecc8
 > 	git revert 52e2bb958ac4f9b3c4bdd78606d279852fd72922
 > 	git revert 88c1863066ccfa456797e12c5d8b4631aa1ad0d0
 > 	git revert 0adab9b9aa18d7e90337d43567f1eec3d5401b81
 > 	git revert 41f4abd92a34f9c5110bbb870c04f8854604e28d
 > 	git revert cb1e78cfa267453bb19e7edafd214c03834b664c
 > 	git revert 87de1cfdc55b16b794e245b07322340725149d62
 > 	git revert 3660c2813fb6d0ba48ee44bcbf9feddf7218c11d
 > 	# Create a revert branch for the rt.2014.02.17b branch
 > 	git checkout -b anti-rt $wherever
 > 	git revert f1f399d1281ea339a08469f7e58193624992f620
 > 	git revert ffa83fb565fbc397cbafb4b71fd1cce276d4c3b6
 > 	git revert 2f33b512a5460578f6cf11d7b7867bed53157c7c
 > 	git merge anti-fixes
 > 
 > Then bisect through these reverts.
 > 
 > I am assuming, perhaps naively, that changes under Documentation and
 > to torture testing should not be affecting you.
 > 
 > Does this make sense?

I tried reverting every one of those and could still hit it, which
seems to indicate the bug is elsewhere, and rcu is just a victim of it.
I'm going to start trying to revert the lockdep changes, given this seems
to happen after that has warned..

	Dave