Date: Tue, 26 May 2009 11:18:00 -0700 From: Kip Macy <kmacy@freebsd.org> To: John Baldwin <jhb@freebsd.org> Cc: src-committers@freebsd.org, svn-src-user@freebsd.org Subject: Re: svn commit: r192604 - in user/kmacy/releng_7_2_fcs/sys: dev/hwpmc sys Message-ID: <3c1674c90905261118y282d9b0fn7d54630f507d8363@mail.gmail.com> In-Reply-To: <200905260830.36831.jhb@freebsd.org> References: <200905222145.n4MLjhm3019802@svn.freebsd.org> <200905260830.36831.jhb@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, May 26, 2009 at 5:30 AM, John Baldwin <jhb@freebsd.org> wrote: > On Friday 22 May 2009 5:45:43 pm Kip Macy wrote: >> Author: kmacy >> Date: Fri May 22 21:45:43 2009 >> New Revision: 192604 >> URL: http://svn.freebsd.org/changeset/base/192604 >> >> Log: >> =A0 - remove pmc_kthread_mtx >> =A0 - replace sleep/wakeup on kthread with a condvar > > If you do not sleep on the kthread/kproc when waiting for a kthread to > exit, then you open up a race window. =A0Usually this matters more for > any kthreads that live in a module since the race allows the module to > be unmapped before the thread is finished executing code from the module > resulting in a fatal page fault in the kernel. Yes, that is why the kthread explicitly calls cv_signal after clearing the kthread pointer. Thanks, Kip
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3c1674c90905261118y282d9b0fn7d54630f507d8363>