Messages in this thread | | | Date | Mon, 8 Jun 2009 12:11:49 +0530 | From | Ananth N Mavinakayanahalli <> | Subject | Re: [PATCH] kmemcheck: move hook before preempt_conditional_sti() |
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On Sun, Jun 07, 2009 at 06:26:52PM +0200, Vegard Nossum wrote: > There are actually two problems here: > > 1. We absolutely cannot enable IRQs in case the fault was caused by > kmemcheck. > > 2. We cannot enable preemption and then return from the debug handler > without disabling preemption afterwards. > > The problem seems to be a merge fallout between three commits: > > commit 3d2a71a596bd9c761c8487a2178e95f8a61da083 > Author: Alexander van Heukelum <heukelum@fastmail.fm> > Date: Tue Sep 30 18:41:37 2008 +0200 > > x86, traps: converge do_debug handlers > > commit 08d68323d1f0c34452e614263b212ca556dae47f > Author: K.Prasad <prasad@linux.vnet.ibm.com> > Date: Mon Jun 1 23:44:08 2009 +0530 > > hw-breakpoints: modifying generic debug exception to use thread-specific deb > > commit 787ecfaa503dc63ff1831ddc74b15dad49bace1d > Author: Vegard Nossum <vegard.nossum@gmail.com> > Date: Fri Apr 4 00:53:23 2008 +0200 > > x86: add hooks for kmemcheck > > I encourage the kprobe developers to check whether their code is correct > as it stands in current tip/master. Also, comments on this particular > change is welcome.
I see no problem with this change wrt kprobes, since the changes happen after the notify_die, by which time, kprobes would've returned NOTIFY_DONE since the per-cpu current_kprobe == NULL.
Ananth
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