From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752474AbZLaCwb (ORCPT ); Wed, 30 Dec 2009 21:52:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752155AbZLaCwa (ORCPT ); Wed, 30 Dec 2009 21:52:30 -0500 Received: from ey-out-2122.google.com ([74.125.78.24]:56203 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751735AbZLaCw3 (ORCPT ); Wed, 30 Dec 2009 21:52:29 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer; b=ja5jsw+E7ATVg95d1WV4u1IpdWoOq0rEgRNP7ZYfPYHk+bCulRt/atZy63kMtjOqj0 RtI+maRQee7w9Fs6JRIZBUNXHOtP0by1xlB9PDkQjg3TNO3dTVIMXsQ1E6MyCrLv5p0r JJHTQ30OAmFpgo/MU/kFCYZ0FgOALem4ZyWcg= From: Frederic Weisbecker To: Ingo Molnar Cc: LKML , Frederic Weisbecker , Peter Zijlstra , Arnaldo Carvalho de Melo , Paul Mackerras Subject: [PATCH] perf: Stop stack frame walking off kernel addresses boundaries Date: Thu, 31 Dec 2009 03:52:25 +0100 Message-Id: <1262227945-27014-1-git-send-regression-fweisbec@gmail.com> X-Mailer: git-send-email 1.6.2.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org While processing kernel perf callchains, an bad entry can be considered as a valid stack pointer but not as a kernel address. In this case, we hang in an endless loop. This can happen in an x86-32 kernel after processing the last entry in a kernel stacktrace. Just stop the stack frame walking after we encounter an invalid kernel address. This fixes a hard lockup in x86-32. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Paul Mackerras --- arch/x86/kernel/dumpstack.c | 14 ++++++++------ 1 files changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index c56bc28..6d81755 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -123,13 +123,15 @@ print_context_stack_bp(struct thread_info *tinfo, while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) { unsigned long addr = *ret_addr; - if (__kernel_text_address(addr)) { - ops->address(data, addr, 1); - frame = frame->next_frame; - ret_addr = &frame->return_address; - print_ftrace_graph_addr(addr, data, ops, tinfo, graph); - } + if (!__kernel_text_address(addr)) + break; + + ops->address(data, addr, 1); + frame = frame->next_frame; + ret_addr = &frame->return_address; + print_ftrace_graph_addr(addr, data, ops, tinfo, graph); } + return (unsigned long)frame; } EXPORT_SYMBOL_GPL(print_context_stack_bp); -- 1.6.2.3