Commit Graph

8 Commits

Author SHA1 Message Date
Dr. David Alan Gilbert c900ef86c5 gdb command: qemu handlers
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 <dgilbert@redhat.com>
Message-id: 1445951385-11924-1-git-send-email-dgilbert@redhat.com

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
 (from_=from_@entry=0x558698cb3cf0, to_=to_@entry=0x7f421c37eac8,
 action=action@entry=COROUTINE_YIELD) 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 (f=f@entry=0x558698c50570)
     at /home/dgilbert/git/qemu/migration/qemu-file.c:604
 #8  0x0000558696347e5c in qemu_loadvm_state (f=f@entry=0x558698c50570)
     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 <stefanha@redhat.com>
2015-10-29 17:59:27 +00:00
Paolo Bonzini a201b0ff28 qemu-gdb: add $qemu_coroutine_sp and $qemu_coroutine_pc
These can be useful to manually get a stack trace of a coroutine inside
a core dump.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1444636974-19950-4-git-send-email-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-29 17:59:26 +00:00
Peter Maydell 30c38c90bd scripts/qemu-gdb: Add brief comment describing usage
Add a brief comment describing how to use the debug support
from GDB.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1439574392-4403-5-git-send-email-peter.maydell@linaro.org
2015-09-11 17:14:50 +01:00
Peter Maydell 5e3c72d41e scripts/qemu-gdb: Silently pass through SIGUSR1
SIGUSR1 is QEMU's IPI signal, and it gets sent a lot, so is
best silently passed through to the guest without stopping.
Make qemu-gdb.py do this bit of configuration for the user.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1439574392-4403-4-git-send-email-peter.maydell@linaro.org
2015-09-11 17:14:50 +01:00
Peter Maydell 191590f09d scripts/qemu-gdb: Split CoroutineCommand into its own file
Split the implementation of CoroutineCommand into its own file.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1439574392-4403-3-git-send-email-peter.maydell@linaro.org
2015-09-11 17:14:49 +01:00
Peter Maydell 93b1b365dc scripts/qemu-gdb: Split MtreeCommand into its own module
As we add more commands to our Python gdb debugging support, it's
going to get unwieldy to have everything in a single file. Split
the implementation of the 'mtree' command from qemu-gdb.py into
its own module.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1439574392-4403-2-git-send-email-peter.maydell@linaro.org
2015-09-11 17:14:49 +01:00
Stefan Hajnoczi 9eddd6a4b3 scripts: add 'qemu coroutine' command to qemu-gdb.py
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>
2015-04-28 15:36:09 +02:00
Avi Kivity 4daa187d49 scripts: add gdb support script
Add a script that enhances gdb to be aware of QEMU data structures.

This patch adds a single gdb command, 'qemu mtree'.  The command is
similar to the monitor's 'info mtree', except that it prints MemoryRegion
addresses, and except for working from a core dump as well as a live instance.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-03-24 12:57:02 +00:00