On 04/24/2017 12:53 PM, Dr. David Alan Gilbert wrote: FWIW, the sending side calltrace looks like:
> Thread 8 (Thread 0x3ff509aa910 (LWP 58594)): #0 0x000003ff9d588ca4 in pthread_join () from target:/lib64/libpthread.so.0 #1 0x0000000001493d4a in qemu_thread_join (thread=0x16c7e78 <current_migration+216>) at /root/qemu/util/qemu-thread-posix.c:504 #2 0x00000000012a0d0e in await_return_path_close_on_source (ms=0x16c7da0 <current_migration>) at /root/qemu/migration/migration.c:1641 #3 0x00000000012a1312 in migration_completion (s=0x16c7da0 <current_migration>, current_active_state=5, old_vm_running=0x3ff509a7789, start_time=0x3ff509a7790) at /root/qemu/migration/migration.c:1860 #4 0x00000000012a17b2 in migration_thread (opaque=0x16c7da0 <current_migration>) at /root/qemu/migration/migration.c:1987 #5 0x000003ff9d587bc4 in start_thread () from target:/lib64/libpthread.so.0 #6 0x000003ff9d48a9f2 in thread_start () from target:/lib64/libc.so.6 Thread 7 (Thread 0x3ff4bfff910 (LWP 58593)): #0 0x000003ff9d5915b6 in recvmsg () from target:/lib64/libpthread.so.0 #1 0x000000000141771a in qio_channel_socket_readv (ioc=0xc9986b0, iov=0x3ff4bffc170, niov=1, fds=0x0, nfds=0x0, errp=0x0) at /root/qemu/io/channel-socket.c:476 #2 0x0000000001411668 in qio_channel_readv_full (ioc=0xc9986b0, iov=0x3ff4bffc170, niov=1, fds=0x0, nfds=0x0, errp=0x0) at /root/qemu/io/channel.c:64 #3 0x000000000141190a in qio_channel_read (ioc=0xc9986b0, buf=0xca23888 "", buflen=32768, errp=0x0) at /root/qemu/io/channel.c:112 #4 0x00000000012ad384 in channel_get_buffer (opaque=0xc9986b0, buf=0xca23888 "", pos=49, size=32768) at /root/qemu/migration/qemu-file-channel.c:78 #5 0x00000000012abb64 in qemu_fill_buffer (f=0xca23850) at /root/qemu/migration/qemu-file.c:295 #6 0x00000000012ac7b2 in qemu_peek_byte (f=0xca23850, offset=0) at /root/qemu/migration/qemu-file.c:555 #7 0x00000000012ac82e in qemu_get_byte (f=0xca23850) at /root/qemu/migration/qemu-file.c:568 #8 0x00000000012acbfa in qemu_get_be16 (f=0xca23850) at /root/qemu/migration/qemu-file.c:640 #9 0x00000000012a0756 in source_return_path_thread (opaque=0x16c7da0 <current_migration>) at /root/qemu/migration/migration.c:1512 #10 0x000003ff9d587bc4 in start_thread () from target:/lib64/libpthread.so.0 #11 0x000003ff9d48a9f2 in thread_start () from target:/lib64/libc.so.6 Thread 6 (Thread 0x3ff511aa910 (LWP 58454)): #0 0x000003ff9d58d450 in pthread_cond_wait@@GLIBC_2.3.2 () from target:/lib64/libpthread.so.0 #1 0x0000000001492fce in qemu_cond_wait (cond=0xc9ca238, mutex=0xc9ca210) at /root/qemu/util/qemu-thread-posix.c:133 #2 0x00000000010c6080 in do_data_decompress (opaque=0xc9ca208) at /root/qemu/migration/ram.c:2277 #3 0x000003ff9d587bc4 in start_thread () from target:/lib64/libpthread.so.0 #4 0x000003ff9d48a9f2 in thread_start () from target:/lib64/libc.so.6 Thread 5 (Thread 0x3ff519aa910 (LWP 58453)): #0 0x000003ff9d58d450 in pthread_cond_wait@@GLIBC_2.3.2 () from target:/lib64/libpthread.so.0 #1 0x0000000001492fce in qemu_cond_wait (cond=0xc9ca1c0, mutex=0xc9ca198) at /root/qemu/util/qemu-thread-posix.c:133 #2 0x00000000010c6080 in do_data_decompress (opaque=0xc9ca190) at /root/qemu/migration/ram.c:2277 #3 0x000003ff9d587bc4 in start_thread () from target:/lib64/libpthread.so.0 #4 0x000003ff9d48a9f2 in thread_start () from target:/lib64/libc.so.6 Thread 4 (Thread 0x3ff98807910 (LWP 58440)): #0 0x000003ff9d58d450 in pthread_cond_wait@@GLIBC_2.3.2 () from target:/lib64/libpthread.so.0 #1 0x0000000001492fce in qemu_cond_wait (cond=0xc9e6930, mutex=0x17116b0 <qemu_global_mutex>) at /root/qemu/util/qemu-thread-posix.c:133 #2 0x000000000107720e in qemu_kvm_wait_io_event (cpu=0xc9a87d0) at /root/qemu/cpus.c:1085 #3 0x00000000010773aa in qemu_kvm_cpu_thread_fn (arg=0xc9a87d0) at /root/qemu/cpus.c:1123 #4 0x000003ff9d587bc4 in start_thread () from target:/lib64/libpthread.so.0 #5 0x000003ff9d48a9f2 in thread_start () from target:/lib64/libc.so.6 Thread 3 (Thread 0x3ff99d7f910 (LWP 58437)): #0 0x000003ff9d47d832 in ppoll () from target:/lib64/libc.so.6 #1 0x000000000148b2fa in qemu_poll_ns (fds=0x3ff940008c0, nfds=1, timeout=-1) at /root/qemu/util/qemu-timer.c:322 #2 0x000000000148f6d2 in aio_poll (ctx=0xc9473c0, blocking=true) at /root/qemu/util/aio-posix.c:622 #3 0x00000000011a7b5e in iothread_run (opaque=0xc947230) at /root/qemu/iothread.c:59 #4 0x000003ff9d587bc4 in start_thread () from target:/lib64/libpthread.so.0 #5 0x000003ff9d48a9f2 in thread_start () from target:/lib64/libc.so.6 Thread 2 (Thread 0x3ff9a57f910 (LWP 58434)): #0 0x000003ff9d484336 in syscall () from target:/lib64/libc.so.6 ---Type <return> to continue, or q <return> to quit--- #1 0x0000000001493636 in qemu_futex_wait (f=0x1b2b9dc <rcu_call_ready_event>, val=4294967295) at /root/qemu/include/qemu/futex.h:26 #2 0x0000000001493838 in qemu_event_wait (ev=0x1b2b9dc <rcu_call_ready_event>) at /root/qemu/util/qemu-thread-posix.c:399 #3 0x00000000014b40a8 in call_rcu_thread (opaque=0x0) at /root/qemu/util/rcu.c:249 #4 0x000003ff9d587bc4 in start_thread () from target:/lib64/libpthread.so.0 #5 0x000003ff9d48a9f2 in thread_start () from target:/lib64/libc.so.6 Thread 1 (Thread 0x3ffb24c5f00 (LWP 58412)): #0 0x000003ff9d47d832 in ppoll () from target:/lib64/libc.so.6 #1 0x000000000148b414 in qemu_poll_ns (fds=0xc98f6e0, nfds=6, timeout=999000000) at /root/qemu/util/qemu-timer.c:334 #2 0x000000000148ccca in os_host_main_loop_wait (timeout=999000000) at /root/qemu/util/main-loop.c:255 #3 0x000000000148ce0a in main_loop_wait (nonblocking=0) at /root/qemu/util/main-loop.c:517 #4 0x00000000011b3cfa in main_loop () at /root/qemu/vl.c:1898 #5 0x00000000011bc3fc in main (argc=91, argv=0x3ffdc87eed8, envp=0x3ffdc87f1b8) at /root/qemu/vl.c:4709