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From: Kevin Wolf <kwolf@redhat.com>
To: qemu-block@nongnu.org
Cc: kwolf@redhat.com, qemu-devel@nongnu.org
Subject: [Qemu-devel] [PULL 22/76] scripts: add 'qemu coroutine' command to qemu-gdb.py
Date: Tue, 28 Apr 2015 17:00:04 +0200	[thread overview]
Message-ID: <1430233258-31807-23-git-send-email-kwolf@redhat.com> (raw)
In-Reply-To: <1430233258-31807-1-git-send-email-kwolf@redhat.com>

From: Stefan Hajnoczi <stefanha@redhat.com>

The 'qemu coroutine <coroutine-address>' GDB command prints the
backtrace for a CoroutineUContext.  This is useful for peeking inside
yielded coroutines that are waiting for file descriptor events, timers,
etc.

For example:

  $ gdb tests/test-coroutine
  (gdb) b test_yield
  (gdb) r
  (gdb) b qemu_coroutine_enter
  (gdb) c
  (gdb) c
  Continuing.

  Breakpoint 2, qemu_coroutine_enter (co=0x555555c66520, opaque=0x0) at qemu-coroutine.c:103
  103	{
  (gdb) source scripts/qemu-gdb.py
  (gdb) qemu coroutine 0x555555c66520
  #0  0x000055555557a740 in qemu_coroutine_switch (from_=<optimized out>, to_=0x7ffff7f90a70, action=COROUTINE_YIELD) at coroutine-ucontext.c:177
  #1  0x0000555555566af9 in yield_5_times (opaque=0x7fffffffdbb7) at tests/test-coroutine.c:107
  #2  0x000055555557a7aa in coroutine_trampoline (i0=<optimized out>, i1=<optimized out>) at coroutine-ucontext.c:80
  #3  0x00007ffff08de000 in __start_context () at /lib64/libc.so.6

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1427409754-8556-1-git-send-email-stefanha@redhat.com
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 scripts/qemu-gdb.py | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/scripts/qemu-gdb.py b/scripts/qemu-gdb.py
index 8a0f305..6c7f4fb 100644
--- a/scripts/qemu-gdb.py
+++ b/scripts/qemu-gdb.py
@@ -22,12 +22,86 @@ def isnull(ptr):
 def int128(p):
     return long(p['lo']) + (long(p['hi']) << 64)
 
+def get_fs_base():
+    '''Fetch %fs base value using arch_prctl(ARCH_GET_FS)'''
+    # %rsp - 120 is scratch space according to the SystemV ABI
+    old = gdb.parse_and_eval('*(uint64_t*)($rsp - 120)')
+    gdb.execute('call arch_prctl(0x1003, $rsp - 120)', False, True)
+    fs_base = gdb.parse_and_eval('*(uint64_t*)($rsp - 120)')
+    gdb.execute('set *(uint64_t*)($rsp - 120) = %s' % old, False, True)
+    return fs_base
+
+def get_glibc_pointer_guard():
+    '''Fetch glibc pointer guard value'''
+    fs_base = get_fs_base()
+    return gdb.parse_and_eval('*(uint64_t*)((uint64_t)%s + 0x30)' % fs_base)
+
+def glibc_ptr_demangle(val, pointer_guard):
+    '''Undo effect of glibc's PTR_MANGLE()'''
+    return gdb.parse_and_eval('(((uint64_t)%s >> 0x11) | ((uint64_t)%s << (64 - 0x11))) ^ (uint64_t)%s' % (val, val, pointer_guard))
+
+def bt_jmpbuf(jmpbuf):
+    '''Backtrace a jmpbuf'''
+    JB_RBX  = 0
+    JB_RBP  = 1
+    JB_R12  = 2
+    JB_R13  = 3
+    JB_R14  = 4
+    JB_R15  = 5
+    JB_RSP  = 6
+    JB_PC   = 7
+
+    old_rbx = gdb.parse_and_eval('(uint64_t)$rbx')
+    old_rbp = gdb.parse_and_eval('(uint64_t)$rbp')
+    old_rsp = gdb.parse_and_eval('(uint64_t)$rsp')
+    old_r12 = gdb.parse_and_eval('(uint64_t)$r12')
+    old_r13 = gdb.parse_and_eval('(uint64_t)$r13')
+    old_r14 = gdb.parse_and_eval('(uint64_t)$r14')
+    old_r15 = gdb.parse_and_eval('(uint64_t)$r15')
+    old_rip = gdb.parse_and_eval('(uint64_t)$rip')
+
+    pointer_guard = get_glibc_pointer_guard()
+    gdb.execute('set $rbx = %s' % jmpbuf[JB_RBX])
+    gdb.execute('set $rbp = %s' % glibc_ptr_demangle(jmpbuf[JB_RBP], pointer_guard))
+    gdb.execute('set $rsp = %s' % glibc_ptr_demangle(jmpbuf[JB_RSP], pointer_guard))
+    gdb.execute('set $r12 = %s' % jmpbuf[JB_R12])
+    gdb.execute('set $r13 = %s' % jmpbuf[JB_R13])
+    gdb.execute('set $r14 = %s' % jmpbuf[JB_R14])
+    gdb.execute('set $r15 = %s' % jmpbuf[JB_R15])
+    gdb.execute('set $rip = %s' % glibc_ptr_demangle(jmpbuf[JB_PC], pointer_guard))
+
+    gdb.execute('bt')
+
+    gdb.execute('set $rbx = %s' % old_rbx)
+    gdb.execute('set $rbp = %s' % old_rbp)
+    gdb.execute('set $rsp = %s' % old_rsp)
+    gdb.execute('set $r12 = %s' % old_r12)
+    gdb.execute('set $r13 = %s' % old_r13)
+    gdb.execute('set $r14 = %s' % old_r14)
+    gdb.execute('set $r15 = %s' % old_r15)
+    gdb.execute('set $rip = %s' % old_rip)
+
 class QemuCommand(gdb.Command):
     '''Prefix for QEMU debug support commands'''
     def __init__(self):
         gdb.Command.__init__(self, 'qemu', gdb.COMMAND_DATA,
                              gdb.COMPLETE_NONE, True)
 
+class CoroutineCommand(gdb.Command):
+    '''Display coroutine backtrace'''
+    def __init__(self):
+        gdb.Command.__init__(self, 'qemu coroutine', gdb.COMMAND_DATA,
+                             gdb.COMPLETE_NONE)
+
+    def invoke(self, arg, from_tty):
+        argv = gdb.string_to_argv(arg)
+        if len(argv) != 1:
+            gdb.write('usage: qemu coroutine <coroutine-pointer>\n')
+            return
+
+        coroutine_pointer = gdb.parse_and_eval(argv[0]).cast(gdb.lookup_type('CoroutineUContext').pointer())
+        bt_jmpbuf(coroutine_pointer['env']['__jmpbuf'])
+
 class MtreeCommand(gdb.Command):
     '''Display the memory tree hierarchy'''
     def __init__(self):
@@ -86,4 +160,5 @@ class MtreeCommand(gdb.Command):
             subregion = subregion['subregions_link']['tqe_next']
 
 QemuCommand()
+CoroutineCommand()
 MtreeCommand()
-- 
1.8.3.1

  parent reply	other threads:[~2015-04-28 15:01 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-28 14:59 [Qemu-devel] [PULL 00/76] Block patches Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 01/76] savevm: create snapshot failed when id_str already exists Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 02/76] MAINTAINERS: Add myself as the maintainer of the Quorum driver Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 03/76] bt-sdp: fix broken uuids power-of-2 calculation Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 04/76] hw/arm/nseries: convert ffs(3) to ctz32() Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 05/76] uninorth: " Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 06/76] Convert (ffs(val) - 1) to ctz32(val) Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 07/76] Convert ffs() != 0 callers to ctz32() Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 08/76] sd: convert sd_normal_command() ffs(3) call " Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 09/76] omap_intc: convert ffs(3) to ctz32() in omap_inth_sir_update() Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 10/76] os-win32: drop ffs(3) prototype Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 11/76] checkpatch: complain about ffs(3) calls Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 12/76] block: Switch to host monotonic clock for IO throttling Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 13/76] aio-posix: move pollfds to thread-local storage Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 14/76] AioContext: acquire/release AioContext during aio_poll Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 15/76] iothread: release iothread around aio_poll Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 16/76] block-backend: Expose bdrv_write_zeroes() Kevin Wolf
2015-04-28 14:59 ` [Qemu-devel] [PULL 17/76] qemu-img convert: Rewrite copying logic Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 18/76] qemu-iotests: Some qemu-img convert tests Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 19/76] blkdebug: Add bdrv_truncate() Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 20/76] vhdx: Fix zero-fill iov length Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 21/76] thread-pool: clean up thread_pool_completion_bh() Kevin Wolf
2015-04-28 15:00 ` Kevin Wolf [this message]
2015-04-28 15:00 ` [Qemu-devel] [PULL 23/76] block/null: Latency simulation by adding new option "latency-ns" Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 24/76] block/null: Support reopen Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 25/76] MAINTAINERS: Add Fam Zheng as Null block driver maintainer Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 26/76] blockjob: Allow nested pause Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 27/76] block: Pause block jobs in bdrv_drain_all Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 28/76] qemu-iotests: Test that "stop" doesn't drain block jobs Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 29/76] blockjob: Update function name in comments Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 30/76] block: avoid unnecessary bottom halves Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 31/76] virtio_blk: comment fix Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 32/76] m25p80: add missing blk_attach_dev_nofail Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 33/76] m25p80: fix s->blk usage before assignment Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 34/76] block: document block-stream in qmp-commands.hx Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 35/76] block: add bdrv_get_device_or_node_name() Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 36/76] block: use bdrv_get_device_or_node_name() in error messages Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 37/76] block: add 'node-name' field to BLOCK_IMAGE_CORRUPTED Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 38/76] Revert "hmp: fix crash in 'info block -n -v'" Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 39/76] qmp: fill in the image field in BlockDeviceInfo Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 40/76] block/iscsi: do not forget to logout from target Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 41/76] block/iscsi: change all iscsilun properties from uint8_t to bool Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 42/76] block/iscsi: rename iscsi_write_protected and let it return void Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 43/76] block/iscsi: store DPOFUA bit from the modesense command Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 44/76] block/iscsi: optimize WRITE10/16 if cache.writeback is not set Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 45/76] block/iscsi: increase retry count Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 46/76] block/iscsi: handle SCSI_STATUS_TASK_SET_FULL Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 47/76] block/iscsi: bump year in copyright notice Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 48/76] block/iscsi: use the allocationmap also if cache.direct=on Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 49/76] docs: incremental backup documentation Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 50/76] qapi: Add optional field "name" to block dirty bitmap Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 51/76] qmp: Ensure consistent granularity type Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 52/76] qmp: Add block-dirty-bitmap-add and block-dirty-bitmap-remove Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 53/76] block: Introduce bdrv_dirty_bitmap_granularity() Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 54/76] hbitmap: cache array lengths Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 55/76] hbitmap: add hbitmap_merge Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 56/76] block: Add bitmap disabled status Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 57/76] block: Add bitmap successors Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 58/76] qmp: Add support of "dirty-bitmap" sync mode for drive-backup Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 59/76] qmp: add block-dirty-bitmap-clear Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 60/76] qmp: Add dirty bitmap status field in query-block Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 61/76] block: add BdrvDirtyBitmap documentation Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 62/76] block: Ensure consistent bitmap function prototypes Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 63/76] block: Resize bitmaps on bdrv_truncate Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 64/76] hbitmap: truncate tests Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 65/76] iotests: add invalid input incremental backup tests Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 66/76] iotests: add QMP event waiting queue Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 67/76] iotests: add simple incremental backup case Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 68/76] iotests: add incremental backup failure recovery test Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 69/76] iotests: add incremental backup granularity tests Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 70/76] block/mirror: Always call block_job_sleep_ns() Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 71/76] block/dmg: make it modular Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 72/76] vmdk: Widen before shifting 32 bit header field Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 73/76] block: replace bdrv_states iteration with bdrv_next() Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 74/76] block: add bdrv_set_dirty()/bdrv_reset_dirty() to block_int.h Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 75/76] block: extract bdrv_setup_io_funcs() Kevin Wolf
2015-04-28 15:00 ` [Qemu-devel] [PULL 76/76] block: move I/O request processing to block/io.c Kevin Wolf
2015-04-28 17:15   ` [Qemu-devel] [Qemu-block] " Eric Blake
2015-04-29  8:27     ` Kevin Wolf
2015-04-28 17:58 ` [Qemu-devel] [PULL 00/76] Block patches Peter Maydell

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