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[Qemu-devel] [PULL 07/12] gdb command: qemu handlers
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 07/12] gdb command: qemu handlers |
Date: |
Thu, 29 Oct 2015 18:09:20 +0000 |
From: "Dr. David Alan Gilbert" <address@hidden>
A new gdb commands are added:
qemu handlers
That dumps an AioContext list (by default qemu_aio_context)
possibly including a backtrace for cases it knows about
(with the verbose option). Intended to help find why something
is hanging waiting for IO.
Use 'qemu handlers --verbose iohandler_ctx' to find out why
your incoming migration is stuck.
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
Message-id: address@hidden
V2:
Merge into one command with optional handlers arg, and only do
backtrace in verbose mode
(gdb) qemu handlers
----
{pfd = {fd = 6, events = 25, revents = 0}, io_read = 0x55869656ffd0
<event_notifier_dummy_cb>, io_write = 0x0, deleted = 0, opaque =
0x558698c4ce08, node = {le_next = 0x0, le_prev = 0x558698c4cdc0}}
(gdb) qemu handlers iohandler_ctx
----
{pfd = {fd = 9, events = 25, revents = 0}, io_read = 0x558696581380
<fd_coroutine_enter>, io_write = 0x0, deleted = 0, opaque =
0x558698dc99d0, node = {le_next = 0x558698c4cca0, le_prev =
0x558698c4c1d0}}
----
{pfd = {fd = 4, events = 25, revents = 0}, io_read = 0x55869657b330
<sigfd_handler>, io_write = 0x0, deleted = 0, opaque = 0x4, node =
{le_next = 0x558698c4c260, le_prev = 0x558699f72508}}
----
{pfd = {fd = 5, events = 25, revents = 0}, io_read = 0x55869656ffd0
<event_notifier_dummy_cb>, io_write = 0x0, deleted = 0, opaque =
0x558698c4c218, node = {le_next = 0x0, le_prev = 0x558698c4ccc8}}
----
(gdb) qemu handlers --verbose iohandler_ctx
----
{pfd = {fd = 9, events = 25, revents = 0}, io_read = 0x558696581380
<fd_coroutine_enter>, io_write = 0x0, deleted = 0, opaque =
0x558698dc99d0, node = {le_next = 0x558698c4cca0, le_prev =
0x558698c4c1d0}}
#0 0x0000558696581820 in qemu_coroutine_switch
(address@hidden, address@hidden,
address@hidden) at
/home/dgilbert/git/qemu/coroutine-ucontext.c:177
#1 0x0000558696580c00 in qemu_coroutine_yield () at
/home/dgilbert/git/qemu/qemu-coroutine.c:145
#2 0x00005586965814f5 in yield_until_fd_readable (fd=9) at
/home/dgilbert/git/qemu/qemu-coroutine-io.c:90
#3 0x0000558696523937 in socket_get_buffer (opaque=0x55869a3dc620,
buf=0x558698c505a0 "", pos=<optimized out>, size=32768) at
/home/dgilbert/git/qemu/migration/qemu-file-unix.c:101
#4 0x0000558696521fac in qemu_fill_buffer (f=0x558698c50570) at
/home/dgilbert/git/qemu/migration/qemu-file.c:227
#5 0x0000558696522989 in qemu_peek_byte (f=0x558698c50570, offset=0)
at /home/dgilbert/git/qemu/migration/qemu-file.c:507
#6 0x0000558696522bf4 in qemu_get_be32 (f=0x558698c50570) at
/home/dgilbert/git/qemu/migration/qemu-file.c:520
#7 0x0000558696522bf4 in qemu_get_be32 (address@hidden)
at /home/dgilbert/git/qemu/migration/qemu-file.c:604
#8 0x0000558696347e5c in qemu_loadvm_state (address@hidden)
at /home/dgilbert/git/qemu/migration/savevm.c:1821
#9 0x000055869651de8c in process_incoming_migration_co
(opaque=0x558698c50570)
at /home/dgilbert/git/qemu/migration/migration.c:336
#10 0x000055869658188a in coroutine_trampoline (i0=<optimized out>,
i1=<optimized out>)
at /home/dgilbert/git/qemu/coroutine-ucontext.c:80
#11 0x00007f420f05df10 in __start_context () at /lib64/libc.so.6
#12 0x00007ffc40815f50 in ()
#13 0x0000000000000000 in ()
----
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
scripts/qemu-gdb.py | 3 ++-
scripts/qemugdb/aio.py | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 60 insertions(+), 1 deletion(-)
create mode 100644 scripts/qemugdb/aio.py
diff --git a/scripts/qemu-gdb.py b/scripts/qemu-gdb.py
index ef2fd19..b3f8e04 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 +37,7 @@ class QemuCommand(gdb.Command):
QemuCommand()
coroutine.CoroutineCommand()
mtree.MtreeCommand()
+aio.HandlersCommand()
coroutine.CoroutineSPFunction()
coroutine.CoroutinePCFunction()
diff --git a/scripts/qemugdb/aio.py b/scripts/qemugdb/aio.py
new file mode 100644
index 0000000..2ba00c4
--- /dev/null
+++ b/scripts/qemugdb/aio.py
@@ -0,0 +1,58 @@
+#!/usr/bin/python
+
+# GDB debugging support: aio/iohandler debug
+#
+# Copyright (c) 2015 Red Hat, Inc.
+#
+# Author: Dr. David Alan Gilbert <address@hidden>
+#
+# 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, verbose):
+ '''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 verbose and 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 HandlersCommand(gdb.Command):
+ '''Display aio handlers'''
+ def __init__(self):
+ gdb.Command.__init__(self, 'qemu handlers', gdb.COMMAND_DATA,
+ gdb.COMPLETE_NONE)
+
+ def invoke(self, arg, from_tty):
+ verbose = False
+ argv = gdb.string_to_argv(arg)
+
+ if len(argv) > 0 and argv[0] == '--verbose':
+ verbose = True
+ argv.pop(0)
+
+ if len(argv) > 1:
+ gdb.write('usage: qemu handlers [--verbose] [handler]\n')
+ return
+
+ if len(argv) == 1:
+ handlers_name = argv[0]
+ else:
+ handlers_name = 'qemu_aio_context'
+ dump_aiocontext(gdb.parse_and_eval(handlers_name), verbose)
--
2.4.3
- [Qemu-devel] [PULL 00/12] Block patches, Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 01/12] qemu-gdb: allow using glibc_pointer_guard() on core dumps, Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 02/12] qemu-gdb: extract parts of "qemu coroutine" implementation, Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 04/12] s390x: include HW_COMPAT_* props, Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 06/12] virtio-blk: switch off scsi-passthrough by default, Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 03/12] qemu-gdb: add $qemu_coroutine_sp and $qemu_coroutine_pc, Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 05/12] ppc/spapr: add 2.4 compat props, Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 07/12] gdb command: qemu handlers,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 08/12] virtio: sync the dataplane vring state to the virtqueue before virtio_save, Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 11/12] target-arm: xlnx-zynqmp: Add sdhci support., Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 10/12] sdhci: Split sdhci.h for public and internal device usage, Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 12/12] block: Consider all child nodes in bdrv_requests_pending(), Stefan Hajnoczi, 2015/10/29
- [Qemu-devel] [PULL 09/12] sd.h: Move sd.h to include/hw/sd/, Stefan Hajnoczi, 2015/10/29
- Re: [Qemu-devel] [PULL 00/12] Block patches, Peter Maydell, 2015/10/30