From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1Td0JL-00052e-RH for kexec@lists.infradead.org; Mon, 26 Nov 2012 15:09:28 +0000 From: ebiederm@xmission.com (Eric W. Biederman) References: <50ADE0C2.1000106@cn.fujitsu.com> <50ADE11A.401@cn.fujitsu.com> Date: Mon, 26 Nov 2012 09:08:54 -0600 In-Reply-To: <50ADE11A.401@cn.fujitsu.com> (Zhang Yanfei's message of "Thu, 22 Nov 2012 16:23:54 +0800") Message-ID: <87ip8sxuyh.fsf@xmission.com> MIME-Version: 1.0 Subject: Re: [PATCH v8 1/2] x86/kexec: add a new atomic notifier list for kdump List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Zhang Yanfei Cc: Marcelo Tosatti , Gleb Natapov , "kvm@vger.kernel.org" , "x86@kernel.org" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" Zhang Yanfei writes: > This patch adds an atomic notifier list named crash_notifier_list. > Currently, when loading kvm-intel module, a notifier will be registered > in the list to enable vmcss loaded on all cpus to be VMCLEAR'd if > needed. crash_notifier_list ick gag please no. Effectively this makes the kexec on panic code path undebuggable. Instead we need to use direct function calls to whatever you are doing. If a direct function call is too complex then the piece of code you want to call is almost certainly too complex to be calling on a code path like this. Eric > Signed-off-by: Zhang Yanfei > --- > arch/x86/include/asm/kexec.h | 2 ++ > arch/x86/kernel/crash.c | 9 +++++++++ > 2 files changed, 11 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h > index 317ff17..5e22b00 100644 > --- a/arch/x86/include/asm/kexec.h > +++ b/arch/x86/include/asm/kexec.h > @@ -163,6 +163,8 @@ struct kimage_arch { > }; > #endif > > +extern struct atomic_notifier_head crash_notifier_list; > + > #endif /* __ASSEMBLY__ */ > > #endif /* _ASM_X86_KEXEC_H */ > diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c > index 13ad899..c5b2f70 100644 > --- a/arch/x86/kernel/crash.c > +++ b/arch/x86/kernel/crash.c > @@ -16,6 +16,8 @@ > #include > #include > #include > +#include > +#include > > #include > #include > @@ -30,6 +32,9 @@ > > int in_crash_kexec; > > +ATOMIC_NOTIFIER_HEAD(crash_notifier_list); > +EXPORT_SYMBOL_GPL(crash_notifier_list); > + > #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC) > > static void kdump_nmi_callback(int cpu, struct pt_regs *regs) > @@ -46,6 +51,8 @@ static void kdump_nmi_callback(int cpu, struct pt_regs *regs) > #endif > crash_save_cpu(regs, cpu); > > + atomic_notifier_call_chain(&crash_notifier_list, 0, NULL); > + > /* Disable VMX or SVM if needed. > * > * We need to disable virtualization on all CPUs. > @@ -88,6 +95,8 @@ void native_machine_crash_shutdown(struct pt_regs *regs) > > kdump_nmi_shootdown_cpus(); > > + atomic_notifier_call_chain(&crash_notifier_list, 0, NULL); > + > /* Booting kdump kernel with VMX or SVM enabled won't work, > * because (among other limitations) we can't disable paging > * with the virt flags. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec