From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: qemu-devel@nongnu.org
Cc: stefanha@redhat.com, pbonzini@redhat.com,
vsementsov@virtuozzo.com, den@openvz.org
Subject: [Qemu-devel] [PATCH 1/4] scripts/qemugdb: get pthread_self from "info threads" command
Date: Wed, 28 Mar 2018 20:32:35 +0300 [thread overview]
Message-ID: <20180328173238.507470-2-vsementsov@virtuozzo.com> (raw)
In-Reply-To: <20180328173238.507470-1-vsementsov@virtuozzo.com>
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 >= 7.3.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
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.
import gdb
+import re
VOID_PTR = gdb.lookup_type('void').pointer()
@@ -28,7 +29,17 @@ def get_fs_base():
return fs_base
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 = gdb.execute('info threads', False, True)
+ m = re.search('^\* 1 Thread (0x[0-9a-f]+)', threads, re.MULTILINE)
+ 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 = gdb.newest_frame()
while f.name() != 'start_thread':
f = f.older()
--
2.11.1
next prev parent reply other threads:[~2018-03-28 17:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-28 17:32 [Qemu-devel] [PATCH 0/4] qemugdb: coroutine backtrace for coredump Vladimir Sementsov-Ogievskiy
2018-03-28 17:32 ` Vladimir Sementsov-Ogievskiy [this message]
2018-04-04 9:52 ` [Qemu-devel] [PATCH 1/4] scripts/qemugdb: get pthread_self from "info threads" command Paolo Bonzini
2018-04-04 9:57 ` Stefan Hajnoczi
2018-03-28 17:32 ` [Qemu-devel] [PATCH 2/4] scripts/qemugdb: improve "qemu coroutine" command Vladimir Sementsov-Ogievskiy
2018-04-04 10:37 ` Stefan Hajnoczi
2018-03-28 17:32 ` [Qemu-devel] [PATCH 3/4] scripts/qemugdb: add coredump.py for coredump patching Vladimir Sementsov-Ogievskiy
2018-03-28 17:32 ` [Qemu-devel] [PATCH 4/4] scripts/qemugdb: backtraces for coroutines in coredump Vladimir Sementsov-Ogievskiy
2018-04-04 10:36 ` Stefan Hajnoczi
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