linux-kernel - [PATCH 2/2] Allow kdump with crash_kexec_post

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Date:	Wed, 13 Jul 2016 14:20:00 +0200
From:	Petr Tesarik <ptesarik@...e.com>
To:	Juergen Gross <jgross@...e.com>,
	Josh Triplett <josh@...htriplett.org>,
	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Eric Biederman <ebiederm@...ssion.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Dave Young <dyoung@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	David Vrabel <david.vrabel@...rix.com>
Cc:	"moderated list:XEN HYPERVISOR INTERFACE" 
	<xen-devel@...ts.xenproject.org>,
	"maintainer:X86 ARCHITECTURE 32-BIT AND 64-BIT" <x86@...nel.org>,
	"open list:KEXEC" <kexec@...ts.infradead.org>,
	open list <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] Allow kdump with crash_kexec_post_notifiers

If a crash kernel is loaded, do not crash the running domain. This is
needed if the kernel is loaded with crash_kexec_post_notifiers, because
panic notifiers are run before __crash_kexec() in that case, and this
Xen hook prevents its being called later.

Signed-off-by: Petr Tesarik <ptesarik@...e.com>
---
 arch/x86/xen/enlighten.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 760789a..6e3e7c6 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1325,7 +1325,8 @@ static void xen_crash_shutdown(struct pt_regs *regs)
 static int
 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
 {
-	xen_reboot(SHUTDOWN_crash);
+	if (!kexec_crash_loaded())
+		xen_reboot(SHUTDOWN_crash);
 	return NOTIFY_DONE;
 }