Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752216Ab3CNFF7 (ORCPT ); Thu, 14 Mar 2013 01:05:59 -0400 Received: from mail-gg0-f181.google.com ([209.85.161.181]:39358 "EHLO mail-gg0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751889Ab3CNFF6 (ORCPT ); Thu, 14 Mar 2013 01:05:58 -0400 From: kpark3469@gmail.com To: linux@arm.linux.org.uk Cc: keun-o.park@windriver.com, dave.martin@linaro.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kpark3469@gmail.com Subject: [PATCH v3] arm: fix a wrong value returned from CALLER_ADDRn Date: Thu, 14 Mar 2013 13:35:01 +0900 Message-Id: <1363235701-21342-1-git-send-email-kpark3469@gmail.com> X-Mailer: git-send-email 1.7.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1857 Lines: 53 From: Sahara This makes return_address() return a correct value for CALLER_ADDRn. To have a correct value from CALLER_ADDRn, we need to fix three points. * The unwind_frame() does not update frame->lr but frame->pc for backtrace. So frame->pc is meaningful for backtrace. * data.level should be adjusted by adding 2 additional iteration levels. With the current +1 level adjustment, the result of CALLER_ADDR1 will be the same return address with CALLER_ADDR0. * The initialization of data.addr to NULL is needed. When unwind_fame() fails right after data.level reaches zero, the routine returns data.addr which has uninitialized garbage value. Signed-off-by: Sahara Reviewed-by: Dave Martin --- arch/arm/kernel/return_address.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/return_address.c b/arch/arm/kernel/return_address.c index 8085417..fafedd8 100644 --- a/arch/arm/kernel/return_address.c +++ b/arch/arm/kernel/return_address.c @@ -26,7 +26,7 @@ static int save_return_addr(struct stackframe *frame, void *d) struct return_address_data *data = d; if (!data->level) { - data->addr = (void *)frame->lr; + data->addr = (void *)frame->pc; return 1; } else { @@ -41,7 +41,8 @@ void *return_address(unsigned int level) struct stackframe frame; register unsigned long current_sp asm ("sp"); - data.level = level + 1; + data.level = level + 2; + data.addr = NULL; frame.fp = (unsigned long)__builtin_frame_address(0); frame.sp = current_sp; -- 1.7.1 -- 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/