Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932240AbbBQMdS (ORCPT ); Tue, 17 Feb 2015 07:33:18 -0500 Received: from ip4-83-240-67-251.cust.nbox.cz ([83.240.67.251]:40273 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755815AbbBQMdP (ORCPT ); Tue, 17 Feb 2015 07:33:15 -0500 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, James Custer , Russ Anderson , Thomas Gleixner , Jiri Slaby Subject: [PATCH 3.12 120/122] x86: UV BAU: Avoid NULL pointer reference in ptc_seq_show Date: Tue, 17 Feb 2015 12:35:07 +0100 Message-Id: <18f12cbe86a5d6d4afc710cd3e3e064898808738.1424099974.git.jslaby@suse.cz> X-Mailer: git-send-email 2.2.2 In-Reply-To: <09e6fe32192a77f6e2e60cc0f4103e630c7ecf20.1424099973.git.jslaby@suse.cz> References: <09e6fe32192a77f6e2e60cc0f4103e630c7ecf20.1424099973.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1721 Lines: 47 From: James Custer 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit fa2a79ce6aef5de35a4d50487da35deb6b634944 upstream. In init_per_cpu(), when get_cpu_topology() fails, init_per_cpu_tunables() is not called afterwards. This means that bau_control->statp is NULL. If a user then reads /proc/sgi_uv/ptc_statistics ptc_seq_show() references a NULL pointer. Therefore, since uv_bau_init calls set_bau_off when init_per_cpu() fails, we add code that detects when the bau is off in ptc_seq_show() to avoid referencing a NULL pointer. Signed-off-by: James Custer Cc: Russ Anderson Link: http://lkml.kernel.org/r/1414952199-185319-2-git-send-email-jcuster@sgi.com Signed-off-by: Thomas Gleixner Signed-off-by: Jiri Slaby --- arch/x86/platform/uv/tlb_uv.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c index efe4d7220397..a6b5affb024a 100644 --- a/arch/x86/platform/uv/tlb_uv.c +++ b/arch/x86/platform/uv/tlb_uv.c @@ -1367,6 +1367,10 @@ static int ptc_seq_show(struct seq_file *file, void *data) } if (cpu < num_possible_cpus() && cpu_online(cpu)) { bcp = &per_cpu(bau_control, cpu); + if (bcp->nobau) { + seq_printf(file, "cpu %d bau disabled\n", cpu); + return 0; + } stat = bcp->statp; /* source side statistics */ seq_printf(file, -- 2.2.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/