From nobody Sun Apr 28 18:26:26 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1522258605934541.134317505169; Wed, 28 Mar 2018 10:36:45 -0700 (PDT) Received: from localhost ([::1]:40302 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1F09-0002tQ-2N for importer@patchew.org; Wed, 28 Mar 2018 13:36:45 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55768) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1EwH-00004x-59 for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f1EwE-0003xM-Hf for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:45 -0400 Received: from relay.sw.ru ([185.231.240.75]:45864) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f1EwE-0003wK-8S for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:42 -0400 Received: from msk-vpn.virtuozzo.com ([195.214.232.6] helo=kvm.sw.ru) by relay.sw.ru with esmtp (Exim 4.90_1) (envelope-from ) id 1f1EwB-0005l7-6d; Wed, 28 Mar 2018 20:32:39 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org Date: Wed, 28 Mar 2018 20:32:35 +0300 Message-Id: <20180328173238.507470-2-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.11.1 In-Reply-To: <20180328173238.507470-1-vsementsov@virtuozzo.com> References: <20180328173238.507470-1-vsementsov@virtuozzo.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 185.231.240.75 Subject: [Qemu-devel] [PATCH 1/4] scripts/qemugdb: get pthread_self from "info threads" command X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pbonzini@redhat.com, vsementsov@virtuozzo.com, stefanha@redhat.com, den@openvz.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" When debugging a coredump, pthread_self can't be obtained from function arch_prctl. Moreover if qemu crashed in coroutine, we can't find 'start_thread' in current stack-trace. So, add a method, actually proposed in 1138f24645e9e, which should work for gdb version >=3D 7.3. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Stefan Hajnoczi --- scripts/qemugdb/coroutine.py | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/scripts/qemugdb/coroutine.py b/scripts/qemugdb/coroutine.py index ab699794ab..ffaa45c464 100644 --- a/scripts/qemugdb/coroutine.py +++ b/scripts/qemugdb/coroutine.py @@ -14,6 +14,7 @@ # GNU GPL, version 2 or (at your option) any later version. =20 import gdb +import re =20 VOID_PTR =3D gdb.lookup_type('void').pointer() =20 @@ -28,7 +29,17 @@ def get_fs_base(): return fs_base =20 def pthread_self(): - '''Fetch pthread_self() from the glibc start_thread function.''' + # Try read pthread_self from gdb command 'info threads'. + # Will fail for old gdb. + try: + threads =3D gdb.execute('info threads', False, True) + m =3D re.search('^\* 1 Thread (0x[0-9a-f]+)', threads, re.MULTI= LINE) + return int(m.group(1), 16) + except TypeError: + # gdb doesn't support third parameter for execute + pass + + # Try fetch pthread_self() from the glibc start_thread function. f =3D gdb.newest_frame() while f.name() !=3D 'start_thread': f =3D f.older() --=20 2.11.1 From nobody Sun Apr 28 18:26:26 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1522258485373276.8559351059811; Wed, 28 Mar 2018 10:34:45 -0700 (PDT) Received: from localhost ([::1]:40287 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1Ey9-0001J4-Da for importer@patchew.org; Wed, 28 Mar 2018 13:34:41 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55769) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1EwH-00004y-5A for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f1EwE-0003x9-HD for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:45 -0400 Received: from relay.sw.ru ([185.231.240.75]:45858) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f1EwE-0003wJ-8F for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:42 -0400 Received: from msk-vpn.virtuozzo.com ([195.214.232.6] helo=kvm.sw.ru) by relay.sw.ru with esmtp (Exim 4.90_1) (envelope-from ) id 1f1EwB-0005l7-CB; Wed, 28 Mar 2018 20:32:39 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org Date: Wed, 28 Mar 2018 20:32:36 +0300 Message-Id: <20180328173238.507470-3-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.11.1 In-Reply-To: <20180328173238.507470-1-vsementsov@virtuozzo.com> References: <20180328173238.507470-1-vsementsov@virtuozzo.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 185.231.240.75 Subject: [Qemu-devel] [PATCH 2/4] scripts/qemugdb: improve "qemu coroutine" command X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pbonzini@redhat.com, vsementsov@virtuozzo.com, stefanha@redhat.com, den@openvz.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" - print regs - catch exception for coredump debugging Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Stefan Hajnoczi --- scripts/qemugdb/coroutine.py | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/scripts/qemugdb/coroutine.py b/scripts/qemugdb/coroutine.py index ffaa45c464..7070a592f3 100644 --- a/scripts/qemugdb/coroutine.py +++ b/scripts/qemugdb/coroutine.py @@ -80,9 +80,8 @@ def get_jmpbuf_regs(jmpbuf): 'r15': jmpbuf[JB_R15], 'rip': glibc_ptr_demangle(jmpbuf[JB_PC], pointer_guard) } =20 -def bt_jmpbuf(jmpbuf): - '''Backtrace a jmpbuf''' - regs =3D get_jmpbuf_regs(jmpbuf) +def bt_regs(regs): + '''Backtrace with specified regs''' old =3D dict() =20 for i in regs: @@ -113,7 +112,18 @@ class CoroutineCommand(gdb.Command): gdb.write('usage: qemu coroutine \n') return =20 - bt_jmpbuf(coroutine_to_jmpbuf(gdb.parse_and_eval(argv[0]))) + jmpbuf =3D coroutine_to_jmpbuf(gdb.parse_and_eval(argv[0])) + regs =3D get_jmpbuf_regs(jmpbuf) + for k, v in regs.iteritems(): + gdb.write('%s: 0x%x\n' %(k,v)) + + gdb.write('\n') + + try: + bt_regs(regs) + except gdb.error: + print "Coroutine backtrace can't be obtained without " \ + "a process to debug." =20 class CoroutineSPFunction(gdb.Function): def __init__(self): --=20 2.11.1 From nobody Sun Apr 28 18:26:26 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1522258485080222.29941574006807; Wed, 28 Mar 2018 10:34:45 -0700 (PDT) Received: from localhost ([::1]:40289 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1EyC-0001OA-8a for importer@patchew.org; Wed, 28 Mar 2018 13:34:44 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55771) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1EwH-000050-5a for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f1EwE-0003x2-H8 for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:45 -0400 Received: from relay.sw.ru ([185.231.240.75]:45872) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f1EwE-0003wL-88 for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:42 -0400 Received: from msk-vpn.virtuozzo.com ([195.214.232.6] helo=kvm.sw.ru) by relay.sw.ru with esmtp (Exim 4.90_1) (envelope-from ) id 1f1EwB-0005l7-HP; Wed, 28 Mar 2018 20:32:39 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org Date: Wed, 28 Mar 2018 20:32:37 +0300 Message-Id: <20180328173238.507470-4-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.11.1 In-Reply-To: <20180328173238.507470-1-vsementsov@virtuozzo.com> References: <20180328173238.507470-1-vsementsov@virtuozzo.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 185.231.240.75 Subject: [Qemu-devel] [PATCH 3/4] scripts/qemugdb: add coredump.py for coredump patching X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pbonzini@redhat.com, vsementsov@virtuozzo.com, stefanha@redhat.com, den@openvz.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The main function is write_regs_to_coredump, which opens coredump file, searches for 'CORE' sign. The first one should correspond to PRSTATUS note for first thread. Patch register values in elf_prstatus structure, going after header with 'CORE' sign. Signed-off-by: Vladimir Sementsov-Ogievskiy --- scripts/qemugdb/coredump.py | 51 +++++++++++++++++++++++++++++++++++++++++= ++++ 1 file changed, 51 insertions(+) create mode 100644 scripts/qemugdb/coredump.py diff --git a/scripts/qemugdb/coredump.py b/scripts/qemugdb/coredump.py new file mode 100644 index 0000000000..8915461886 --- /dev/null +++ b/scripts/qemugdb/coredump.py @@ -0,0 +1,51 @@ +# Coredump patching +# +# Copyright (c) 2018 Virtuozzo International GmbH. All rights reserved. +# +# Authors: +# Vladimir Sementsov-Ogievskiy +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . +# + +import struct +import shutil + +def write_regs_to_coredump(fname, set_regs): + # asm/ptrace.h + pt_regs =3D ['r15', 'r14', 'r13', 'r12', 'rbp', 'rbx', 'r11', 'r10', + 'r9', 'r8', 'rax', 'rcx', 'rdx', 'rsi', 'rdi', 'orig_rax', + 'rip', 'cs', 'eflags', 'rsp', 'ss'] + + with open(fname, 'r+b') as f: + print 'patching core file "%s"' % fname + + while f.read(4) !=3D 'CORE': + pass + + print 'found "CORE" at 0x%x' % f.tell() + f.seek(4, 1) # go to elf_prstatus + f.seek(112, 1) # offsetof(struct elf_prstatus, pr_reg) + + print 'assume pt_regs at 0x%x' % f.tell() + for reg in pt_regs: + if reg in set_regs: + print 'write %s at 0x%x' % (reg, f.tell()) + f.write(struct.pack('q', set_regs[reg])) + else: + f.seek(8, 1) + +def clone_coredump(source, target, set_regs): + shutil.copyfile(source, target) + write_regs_to_coredump(target, set_regs) --=20 2.11.1 From nobody Sun Apr 28 18:26:26 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 15222586047831022.7896711945506; Wed, 28 Mar 2018 10:36:44 -0700 (PDT) Received: from localhost ([::1]:40301 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1F08-0002sr-0v for importer@patchew.org; Wed, 28 Mar 2018 13:36:44 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55772) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1EwH-000051-5o for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f1EwE-0003x5-Gx for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:45 -0400 Received: from relay.sw.ru ([185.231.240.75]:45856) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f1EwE-0003wI-8A for qemu-devel@nongnu.org; Wed, 28 Mar 2018 13:32:42 -0400 Received: from msk-vpn.virtuozzo.com ([195.214.232.6] helo=kvm.sw.ru) by relay.sw.ru with esmtp (Exim 4.90_1) (envelope-from ) id 1f1EwB-0005l7-MS; Wed, 28 Mar 2018 20:32:39 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org Date: Wed, 28 Mar 2018 20:32:38 +0300 Message-Id: <20180328173238.507470-5-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.11.1 In-Reply-To: <20180328173238.507470-1-vsementsov@virtuozzo.com> References: <20180328173238.507470-1-vsementsov@virtuozzo.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 185.231.240.75 Subject: [Qemu-devel] [PATCH 4/4] scripts/qemugdb: backtraces for coroutines in coredump X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pbonzini@redhat.com, vsementsov@virtuozzo.com, stefanha@redhat.com, den@openvz.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" We can't get coroutine backtrace through obvious way - set regs - bt - restore regs when debugging a coredump. So, let's go hard way: clone current coredump file, patch regs in it and execute a subprocess gdb to get backtrace from this patched coredump. Signed-off-by: Vladimir Sementsov-Ogievskiy --- scripts/qemugdb/coroutine.py | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) diff --git a/scripts/qemugdb/coroutine.py b/scripts/qemugdb/coroutine.py index 7070a592f3..2a05851e24 100644 --- a/scripts/qemugdb/coroutine.py +++ b/scripts/qemugdb/coroutine.py @@ -15,9 +15,32 @@ =20 import gdb import re +import tempfile +import subprocess +import os +import coredump =20 VOID_PTR =3D gdb.lookup_type('void').pointer() =20 +def bt_regs_static(regs): + files =3D gdb.execute('info files', False, True).split('\n') + executable =3D re.match('^Symbols from "(.*)".$', files[0]).group(1) + dump =3D re.search("`(.*)'", files[2]).group(1) + + with tempfile.NamedTemporaryFile(dir=3D'/tmp', delete=3DFalse) as f: + temp =3D f.name + + coredump.clone_coredump(dump, temp, regs) + + cmd =3D ['gdb', '-batch', '-ex', "python print '----split----'", + '-ex', 'bt', executable, temp] + out =3D subprocess.check_output(cmd) + out =3D out.split('----split----')[1] + + os.remove(temp) + + print out + def get_fs_base(): '''Fetch %fs base value using arch_prctl(ARCH_GET_FS). This is pthread_self().''' @@ -122,8 +145,7 @@ class CoroutineCommand(gdb.Command): try: bt_regs(regs) except gdb.error: - print "Coroutine backtrace can't be obtained without " \ - "a process to debug." + bt_regs_static(regs) =20 class CoroutineSPFunction(gdb.Function): def __init__(self): --=20 2.11.1