From: Greg KH Subject: [14/59] x86, apic: Fix apic=debug boot crash Date: Tue, 24 Aug 2010 15:24:26 -0700 Message-ID: <20100824222523.628108472@clark.site> References: <20100824224625.GA5449@kroah.com> Return-path: In-Reply-To: <20100824224625.GA5449@kroah.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: jeremy@goop.org, xen-devel@lists.xensource.com, konrad.wilk@oracle.com, Ingo Molnar , alan@lxorguk.ukuu.org.uk, akpm@linux-foundation.org, torvalds@linux-foundation.org, stable-review@kernel.org, Daniel Kiper List-Id: xen-devel@lists.xenproject.org 2.6.32-stable review patch. If anyone has any objections, please let us know. ------------------ From: Daniel Kiper commit 05e407603e527f9d808dd3866d3a17c2ce4dfcc5 upstream. Fix a boot crash when apic=debug is used and the APIC is not properly initialized. This issue appears during Xen Dom0 kernel boot but the fix is generic and the crash could occur on real hardware as well. Signed-off-by: Daniel Kiper Cc: xen-devel@lists.xensource.com Cc: konrad.wilk@oracle.com Cc: jeremy@goop.org LKML-Reference: <20100819224616.GB9967@router-fw-old.local.net-space.pl> Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/apic/io_apic.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1736,6 +1736,8 @@ __apicdebuginit(void) print_IO_APIC(void struct irq_pin_list *entry; cfg = desc->chip_data; + if (!cfg) + continue; entry = cfg->irq_2_pin; if (!entry) continue;