From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
Two new gdb commands are added:
qemu iohandlers
that dumps the list of waiting iohandlers, this is particularly
useful for trying to figure out where an incoming migration is
blocked. For 'fd_coroutine_enter' cases we dump a full backtrace.
qemu aios
that dumps the qemu_aio_context list.
This is a rewrite of an earlier version prior to Fam's changes
to the corresponding structures.
Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
(gdb) qemu aios
----
{pfd = {fd = 12, events = 25, revents = 0}, io_read = 0x5634d4033cc0
<qemu_laio_completion_cb>, io_write = 0x0, deleted = 0, opaque =
0x5634d601e8b8, node = {le_next = 0x5634d5fd2330, le_prev =
0x5634d5fd22a0}}
----
{pfd = {fd = 6, events = 25, revents = 0}, io_read = 0x5634d3ff1750
<event_notifier_dummy_cb>, io_write = 0x0, deleted = 0, opaque =
0x5634d5fd22e8, node = {le_next = 0x0, le_prev = 0x5634d5fe8458}}
----
(gdb) qemu iohandlers
----
{pfd = {fd = 15, events = 25, revents = 0}, io_read = 0x559a843bd850
<fd_coroutine_enter>, io_write = 0x0, deleted = 0, opaque =
0x7fef1c5fed30, node = {le_next = 0x559a84e9d180, le_prev =
0x559a84e9c6b0}}
#0 0x0000559a843bdcf0 in qemu_coroutine_switch
(from_=from_@entry=0x559a865fd8e0, to_=to_@entry=0x7fef37774ac8,
action=action@entry=COROUTINE_YIELD) at
/home/dgilbert/git/qemu-world3/coroutine-ucontext.c:177
#1 0x0000559a843bd0d0 in qemu_coroutine_yield () at
/home/dgilbert/git/qemu-world3/qemu-coroutine.c:145
#2 0x0000559a843bd9c5 in yield_until_fd_readable (fd=15) at
/home/dgilbert/git/qemu-world3/qemu-coroutine-io.c:90
#3 0x0000559a84362337 in socket_get_buffer (opaque=0x559a862f7a00,
buf=0x559a84ea0a70 "", pos=<optimized out>, size=32768) at
/home/dgilbert/git/qemu-world3/migration/qemu-file-unix.c:69
#4 0x0000559a84360c9c in qemu_fill_buffer (f=0x559a84ea0a40)
at /home/dgilbert/git/qemu-world3/migration/qemu-file.c:215
#5 0x0000559a84361569 in qemu_peek_byte (f=0x559a84ea0a40, offset=0)
at /home/dgilbert/git/qemu-world3/migration/qemu-file.c:448
#6 0x0000559a843617d4 in qemu_get_be32 (f=0x559a84ea0a40)
at /home/dgilbert/git/qemu-world3/migration/qemu-file.c:461
#7 0x0000559a843617d4 in qemu_get_be32 (f=f@entry=0x559a84ea0a40)
at /home/dgilbert/git/qemu-world3/migration/qemu-file.c:545
#8 0x0000559a84187d92 in qemu_loadvm_state (f=f@entry=0x559a84ea0a40)
at /home/dgilbert/git/qemu-world3/migration/savevm.c:1070
#9 0x0000559a8435dc42 in process_incoming_migration_co
(opaque=0x559a84ea0a40)
at /home/dgilbert/git/qemu-world3/migration/migration.c:285
#10 0x0000559a843bdd5a in coroutine_trampoline (i0=<optimized out>,
i1=<optimized out>)
at /home/dgilbert/git/qemu-world3/coroutine-ucontext.c:80
#11 0x00007fef2a462f10 in __start_context () at /lib64/libc.so.6
#12 0x00007fffb7437b50 in ()
#13 0x0000000000000000 in ()
----
{pfd = {fd = 4, events = 25, revents = 0}, io_read = 0x559a843b7800
<sigfd_handler>, io_write = 0x0, deleted = 0, opaque = 0x4, node =
{le_next = 0x559a84e9c740, le_prev = 0x559a86325498}}
----
{pfd = {fd = 5, events = 25, revents = 0}, io_read = 0x559a843ac750
<event_notifier_dummy_cb>, io_write = 0x0, deleted = 0, opaque =
0x559a84e9c6f8, node = {le_next = 0x0, le_prev = 0x559a84e9d1a8}}
----
---
scripts/qemu-gdb.py | 4 +++-
scripts/qemugdb/aio.py | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 55 insertions(+), 1 deletion(-)
create mode 100644 scripts/qemugdb/aio.py
diff --git a/scripts/qemu-gdb.py b/scripts/qemu-gdb.py
index d6f2e5a..99344c7 100644
--- a/scripts/qemu-gdb.py
+++ b/scripts/qemu-gdb.py
@@ -26,7 +26,7 @@ import os, sys
sys.path.append(os.path.dirname(__file__))
-from qemugdb import mtree, coroutine
+from qemugdb import aio, mtree, coroutine
class QemuCommand(gdb.Command):
'''Prefix for QEMU debug support commands'''
@@ -37,6 +37,8 @@ class QemuCommand(gdb.Command):
QemuCommand()
coroutine.CoroutineCommand()
mtree.MtreeCommand()
+aio.IOhandlersCommand()
+aio.AIOsCommand()
# Default to silently passing through SIGUSR1, because QEMU sends it
# to itself a lot.
diff --git a/scripts/qemugdb/aio.py b/scripts/qemugdb/aio.py
new file mode 100644
index 0000000..cda2c37
--- /dev/null
+++ b/scripts/qemugdb/aio.py
@@ -0,0 +1,52 @@
+#!/usr/bin/python
+
+# GDB debugging support: aio/iohandler debug
+#
+# Copyright (c) 2015 Red Hat, Inc.
+#
+# Author: Dr. David Alan Gilbert <dgilb...@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later. See the COPYING file in the top-level directory.
+#
+
+import gdb
+from qemugdb import coroutine
+
+def isnull(ptr):
+ return ptr == gdb.Value(0).cast(ptr.type)
+
+def dump_aiocontext(context):
+ '''Display a dump and backtrace for an aiocontext'''
+ cur = context['aio_handlers']['lh_first']
+ # Get pointers to functions we're going to process specially
+ sym_fd_coroutine_enter = gdb.parse_and_eval('fd_coroutine_enter')
+
+ while not isnull(cur):
+ entry = cur.dereference()
+ gdb.write('----\n%s\n' % entry)
+ if cur['io_read'] == sym_fd_coroutine_enter:
+ coptr =
(cur['opaque'].cast(gdb.lookup_type('FDYieldUntilData').pointer()))['co']
+ coptr = coptr.cast(gdb.lookup_type('CoroutineUContext').pointer())
+ coroutine.bt_jmpbuf(coptr['env']['__jmpbuf'])
+ cur = cur['node']['le_next'];
+
+ gdb.write('----\n')
+
+class AIOsCommand(gdb.Command):
+ '''Display aio handlers'''
+ def __init__(self):
+ gdb.Command.__init__(self, 'qemu aios', gdb.COMMAND_DATA,
+ gdb.COMPLETE_NONE)
+
+ def invoke(self, arg, from_tty):
+ dump_aiocontext(gdb.parse_and_eval('qemu_aio_context'))
+
+class IOhandlersCommand(gdb.Command):
+ '''Display io handlers'''
+ def __init__(self):
+ gdb.Command.__init__(self, 'qemu iohandlers', gdb.COMMAND_DATA,
+ gdb.COMPLETE_NONE)
+
+ def invoke(self, arg, from_tty):
+ dump_aiocontext(gdb.parse_and_eval('iohandler_ctx'))
--
2.5.0
