From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755228AbaHKWYc (ORCPT ); Mon, 11 Aug 2014 18:24:32 -0400 Received: from mail-qc0-f169.google.com ([209.85.216.169]:53186 "EHLO mail-qc0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755210AbaHKWYa (ORCPT ); Mon, 11 Aug 2014 18:24:30 -0400 From: Sadasivan Shaiju MIME-Version: 1.0 X-Mailer: Microsoft Outlook 14.0 Thread-Index: Ac+1spUmo2L4mFl6Snei/0roXqshnQ== Date: Mon, 11 Aug 2014 15:24:18 -0700 Message-ID: Subject: PATCH -RCU locking on last_VFP_context[cpu] in vfp_notifier [2.6.32] To: linux@arm.linux.org.uk Cc: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi , I work for Montavista (Cavium Inc) as a Technical Lead . I want to push some of the kernel patches to rt community (2.6.32 kernel 2.6.33 rt patch) , so that It will go to the main line These patches are reviewed and approved by our system Architect. I request you to include in the main line . These issues were reported during econa board bringup at montavista. Problem Description: Using cge60-econa-cns3420-2.6.32, the kernel failed to boot with the following error: Internal error: Oops: 817 [#1] from cpu 1 PREEMPT SMP last sysfs file: /sys/devices/virtual/bdi/0:19/uevent Modules linked in: hmac ctr deflate CPU: 1 Tainted: G W (2.6.32.46.cge #1) PC is at vfp_notifier+0x48/0xbc LR is at vfp_notifier+0x44/0xbc pc : [] lr : [] psr: 60000013 sp : aeee1d30 ip : aeee1d50 fp : aeee1d4c r10: af8d6460 r9 : ffffffff r8 : af88c000 r7 : a05ba584 r6 : af88c000 r5 : 00000001 r4 : 40000000 r3 : 00000000 r2 : 00000000 r1 : 40000000 r0 : aeee0230 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 00c5787d Table: 2eeec00a DAC: 00000017 Process grep (pid: 1710, stack limit = 0xaeee0270) Stack: from cpu 1 (0xaeee1d30 to 0xaeee2000) Root Cause: On the SMP architecture, last_VFP_context[cpu] becomes NULL because it gets released on a different CPU. How Solved: Fixed by exiting the thread instead of releasing the thread in the vfp_notifier. I request you to include the above patch to the main line kernel . If any questions please contact me at sshaiju@mvista.com (shaiju_sada@yahoo.com) Regards, Shaiju.