On Tuesday, October 20, 2015 08:29:21 PM Konstantin Belousov wrote: > Author: kib > Date: Tue Oct 20 20:29:21 2015 > New Revision: 289661 > URL: https://svnweb.freebsd.org/changeset/base/289661 > > Log: > Mark struct thread zone as type-stable. > > When establishing the locking state for several lock types (including > blockable mutexes and sx) failed, locking primitives try to spin while > the owner thread is running. The spinning loop performs the test for > running condition by dereferencing the owner->td_state field of the > owner thread. If the owner thread exited while spinner was put off > the processor, it is harmless to access reused struct thread owner, > since in some near future the current processor would notice the owner > change and make appropriate progress. But it could be that the page > which carried the freed struct thread was unmapped, then we fault > (this cannot happen on amd64). > > For now, disallowing free of the struct thread seems to be good > enough, and tests which create a lot of threads once, did not > demonstrated regressions. > > Reviewed by: jhb, pho > Reported and tested by: pho > Sponsored by: The FreeBSD Foundation > MFC after: 2 weeks > Differential revision: https://reviews.freebsd.org/D3908
PR: 65448 -- John Baldwin _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
