From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate4.de.ibm.com (8.13.8/8.13.8) with ESMTP id m5I8ZPtb100234 for ; Wed, 18 Jun 2008 08:35:25 GMT Received: from d12av02.megacenter.de.ibm.com (d12av02.megacenter.de.ibm.com [9.149.165.228]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v9.0) with ESMTP id m5I8ZPph3129528 for ; Wed, 18 Jun 2008 10:35:25 +0200 Received: from d12av02.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av02.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m5I8ZOr7013180 for ; Wed, 18 Jun 2008 10:35:25 +0200 Message-ID: <4858C8CC.4040407@de.ibm.com> Date: Wed, 18 Jun 2008 10:35:24 +0200 From: Peter Oberparleiter MIME-Version: 1.0 Subject: Re: 2.6.26-rc5-mm1 References: <200806180026.27247.m.kozlowski@tuxland.pl> In-Reply-To: <200806180026.27247.m.kozlowski@tuxland.pl> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Mariusz Kozlowski , Andrew Morton Cc: linux-mm@kvack.org, balbir@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, Peter Oberparleiter List-ID: Mariusz Kozlowski wrote: > After a few hours and tons of reboots I narrowed it down to > arch/x86/kernel/Makefile: > > a) works > obj-y += tsc_$(BITS).o io_delay.o rtc.o > GCOV_tsc_$(BITS).o := n > #GCOV_io_delay.o := n > #GCOV_rtc.o := n > > b) doesn't work > obj-y += tsc_$(BITS).o io_delay.o rtc.o > #GCOV_tsc_$(BITS).o := n > #GCOV_io_delay.o := n > #GCOV_rtc.o := n > > and that points to arch/x86/kernel/tsc_64.c Excellent work! I had a quick look at that file and couldn't identify any obvious reason (for a non-x84 developer) why it shouldn't work with -fprofile-arcs. There are some comments in the corresponding Makefile though that indicate that tsc_64.o is a bit picky with regards to CFLAGS (no -pg, -fno-stack-protector) so I think it's safe to simply exclude those files from profiling. Based on your findings, the following patch should be applied to -mm. Thanks again for your effort. -- [PATCH] gcov: fix run-time error on x86_64 From: Peter Oberparleiter Disable profiling of tsc_$(BITS).o to fix a run-time error when using CONFIG_GCOV_PROFILE_ALL on x86_64: bash[498] segfault at ffffffff80868b58 ip ffffffffff600412 sp 7fffa3d010f0 error 7 init[1] segfault at ffffffff80868b58 ip ffffffffff600412 sp 7fff9e97f640 error 7 init[1] segfault at ffffffff80868b58 ip ffffffffff600412 sp 7fff9e97eed0 error 7 Kernel panic - not syncing: Attemted to kill init! Pid 1, comm: init Not tainted 2.6.26-rc5-mm1 #1 m.kozlowski@tuxland.pl wrote: > After a few hours and tons of reboots I narrowed it down to > arch/x86/kernel/Makefile: > > a) works > obj-y += tsc_$(BITS).o io_delay.o rtc.o > GCOV_tsc_$(BITS).o := n > #GCOV_io_delay.o := n > #GCOV_rtc.o := n > > b) doesn't work > obj-y += tsc_$(BITS).o io_delay.o rtc.o > #GCOV_tsc_$(BITS).o := n > #GCOV_io_delay.o := n > #GCOV_rtc.o := n > > and that points to arch/x86/kernel/tsc_64.c Reported-by: Mariusz Kozlowski Reported-by: Balbir Singh Signed-off-by: Peter Oberparleiter --- arch/x86/kernel/Makefile | 3 +++ 1 file changed, 3 insertions(+) Index: linux-2.6.26-rc5-mm3/arch/x86/kernel/Makefile =================================================================== --- linux-2.6.26-rc5-mm3.orig/arch/x86/kernel/Makefile +++ linux-2.6.26-rc5-mm3/arch/x86/kernel/Makefile @@ -13,6 +13,9 @@ CFLAGS_REMOVE_tsc_32.o = -pg CFLAGS_REMOVE_rtc.o = -pg endif +GCOV_tsc_32.o := n +GCOV_tsc_64.o := n + # # vsyscalls (which work on the user stack) should have # no stack-protector checks: -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org