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c5e76115cc
When cancel migration during RDMA precopy, the source qemu main thread hangs sometime.
The backtrace is:
(gdb) bt
#0 0x00007f249eabd43d in write () from /lib64/libpthread.so.0
#1 0x00007f24a1ce98e4 in rdma_get_cm_event (channel=0x4675d10, event=0x7ffe2f643dd0) at src/cma.c:2189
#2 0x00000000007b6166 in qemu_rdma_cleanup (rdma=0x6784000) at migration/rdma.c:2296
#3 0x00000000007b7cae in qio_channel_rdma_close (ioc=0x3bfcc30, errp=0x0) at migration/rdma.c:2999
#4 0x00000000008db60e in qio_channel_close (ioc=0x3bfcc30, errp=0x0) at io/channel.c:273
#5 0x00000000007a8765 in channel_close (opaque=0x3bfcc30) at migration/qemu-file-channel.c:98
#6 0x00000000007a71f9 in qemu_fclose (f=0x527c000) at migration/qemu-file.c:334
#7 0x0000000000795b96 in migrate_fd_cleanup (opaque=0x3b46280) at migration/migration.c:1162
#8 0x000000000093a71b in aio_bh_call (bh=0x3db7a20) at util/async.c:90
#9 0x000000000093a7b2 in aio_bh_poll (ctx=0x3b121c0) at util/async.c:118
#10 0x000000000093f2ad in aio_dispatch (ctx=0x3b121c0) at util/aio-posix.c:436
#11 0x000000000093ab41 in aio_ctx_dispatch (source=0x3b121c0, callback=0x0, user_data=0x0)
at util/async.c:261
#12 0x00007f249f73c7aa in g_main_context_dispatch () from /lib64/libglib-2.0.so.0
#13 0x000000000093dc5e in glib_pollfds_poll () at util/main-loop.c:215
#14 0x000000000093dd4e in os_host_main_loop_wait (timeout=28000000) at util/main-loop.c:263
#15 0x000000000093de05 in main_loop_wait (nonblocking=0) at util/main-loop.c:522
#16 0x00000000005bc6a5 in main_loop () at vl.c:1944
#17 0x00000000005c39b5 in main (argc=56, argv=0x7ffe2f6443f8, envp=0x3ad0030) at vl.c:4752
It does not get the RDMA_CM_EVENT_DISCONNECTED event after rdma_disconnect sometime.
According to IB Spec once active side send DREQ message, it should wait for DREP message
and only once it arrived it should trigger a DISCONNECT event. DREP message can be dropped
due to network issues.
For that case the spec defines a DREP_timeout state in the CM state machine, if the DREP is
dropped we should get a timeout and a TIMEWAIT_EXIT event will be trigger.
Unfortunately the current kernel CM implementation doesn't include the DREP_timeout state
and in above scenario we will not get DISCONNECT or TIMEWAIT_EXIT events.
So it should not invoke rdma_get_cm_event which may hang forever, and the event channel
is also destroyed in qemu_rdma_cleanup.
Signed-off-by: Lidong Chen <lidongchen@tencent.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
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|---|---|---|
| .. | ||
| block-dirty-bitmap.c | ||
| block.c | ||
| block.h | ||
| channel.c | ||
| channel.h | ||
| colo-comm.c | ||
| colo-failover.c | ||
| colo.c | ||
| exec.c | ||
| exec.h | ||
| fd.c | ||
| fd.h | ||
| global_state.c | ||
| Makefile.objs | ||
| migration.c | ||
| migration.h | ||
| page_cache.c | ||
| page_cache.h | ||
| postcopy-ram.c | ||
| postcopy-ram.h | ||
| qemu-file-channel.c | ||
| qemu-file-channel.h | ||
| qemu-file.c | ||
| qemu-file.h | ||
| qjson.c | ||
| qjson.h | ||
| ram.c | ||
| ram.h | ||
| rdma.c | ||
| rdma.h | ||
| savevm.c | ||
| savevm.h | ||
| socket.c | ||
| socket.h | ||
| tls.c | ||
| tls.h | ||
| trace-events | ||
| vmstate-types.c | ||
| vmstate.c | ||
| xbzrle.c | ||
| xbzrle.h | ||