Re: [Crash-utility] [PATCH][v2] Remove __exception_text_start and __exception_text_end for ARM64

Hi Prabhakar, On Mon, Dec 30, 2019 at 9:55 AM Prabhakar Kushwaha <prabhakar.pkin(a)gmail.com&gt; wrote: > > Dear Bhupesh, > > On Tue, Dec 24, 2019 at 9:39 AM Prabhakar Kushwaha > <prabhakar.pkin(a)gmail.com&gt; wrote: > > > > On Tue, Dec 24, 2019 at 1:09 AM Bhupesh Sharma <bhsharma(a)redhat.com&gt; > wrote: > > > > > > On Mon, Dec 23, 2019 at 7:49 PM Prabhakar Kushwaha > > > <prabhakar.pkin(a)gmail.com&gt; wrote: > > > > > > > > On Mon, Dec 23, 2019 at 7:32 PM Dave Anderson > <anderson(a)redhat.com&gt; wrote: > > > > > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > __exception_text_start and __exception_text_end is used to > group functions > > > > > > and place according to linker script in such a way to achieve > > > > > > kprobe blacklist. Linux commit b6e43c0e3129 ("arm64: remove > __exception > > > > > > annotations") has removed __exception_text_start and > > > > > > __exception_text_end and uses NOKPROBE_SYMBOL() for blacklist > kprobes. > > > > > > > > > > > > So removing references of __exception_text_start and > __exception_text_end > > > > > > for ARM64. > > > > > > > > > > NAK for a couple of reasons... > > > > > > > > > > First, they cannot be removed for backward-compatibility > purposes, and secondly > > > > > an alternative method is required for arm64_back_trace_cmd() for > handling > > > > > exception frames. > > > > > > > > > > > > > We are getting following error with crash tool with latest kernel. > > > > crash: cannot resolve "__exception_text_start" error > > > > > > > > it is because of Linux commit b6e43c0e3129 which removes > > > > __exception_text_start and __exception_text_end. > > > > We need to find alternate way of fixing it. > > > > > > I cannot seem to remember reproducing this issue with crash with > > > latest kernel on my arm64 boards. > > > Can you be more specific on the exact kernel version and the crash > > > command you used, just to be sure we are able to reproduce the same? > > > > > > > We are seeing this issue on Thuder X platform (arm64). > > > > Please find details of commit id. > > A) crash tool: https://github.com/crash-utility/crash.git > > commit: af7f78dc501b8acf7fee3f924f69e93513d0a74b (Fix for the "log > -a" option.) > > > > B) Linux: > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > commit: 46cf053efec6a3a5f343fead837777efe8252a46 (Linux 5.5-rc3) > > > > C) Kexec: > https://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git > > commit: bd077966e2b9041c24df5b689e67670f02be7b0d (kexec-tools: Fix > > conversion overflow when compiling on 32-bit platforms) > > > > > > Logs > > root@ubuntu$ ./crash /proc/vmcore /usr/src/tovards/linux/vmlinux > > > > crash 7.2.7++ > > Copyright (C) 2002-2019 Red Hat, Inc. > > Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation > > Copyright (C) 1999-2006 Hewlett-Packard Co > > Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited > > Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. > > Copyright (C) 2005, 2011 NEC Corporation > > Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc. > > Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc. > > This program is free software, covered by the GNU General Public > License, > > and you are welcome to change it and/or distribute copies of it under > > certain conditions. Enter "help copying" to see the conditions. > > This program has absolutely no warranty. Enter "help warranty" for > details. > > > > vmcoreinfo : vabits_actual: 48 > > GNU gdb (GDB) 7.6 > > Copyright (C) 2013 Free Software Foundation, Inc. > > License GPLv3+: GNU GPL version 3 or later > <http://gnu.org/licenses/gpl.html> > > This is free software: you are free to change and redistribute it. > > There is NO WARRANTY, to the extent permitted by law. Type "show > copying" > > and "show warranty" for details. > > This GDB was configured as "aarch64-unknown-linux-gnu". > > For bug reporting instructions, please see: > > <http://www.gnu.org/software/gdb/bugs/>... > > > > crash: cannot resolve "__exception_text_start" > > > > i hope you got sometime to reproduce this issue. > It can also be seen on Linux 5.5-rc4 tag > (fd6988496e79a6a4bdb514a4655d2920209eb85d). > > crash-util commit 5e975dd8c817ea6aea35e1e15b83c378aee9c136 (HEAD -> > master, origin/master, origin/HEAD) I was able to reproduce the issue with latest Linus's tree. I am working on a patch (as per Dave's suggestion) to fix backward compatibility as well as 'arm64_back_trace_cmd()' (bt command support) and will post it out soon (I am hoping to post out a version after the new year break). Thanks and a Happy New Year, Bhupesh