It looks like your stack trace includes a call to grpc_server_request_registered_call with a NULL server. That is suspicious.
On Tue, Sep 19, 2017 at 8:41 AM ryan via grpc.io <[email protected]> wrote: > > Hello all - > > I've been developing a gRPC-HHVM extension > <https://github.com/grpc/grpc/pull/11553>. In the process of stress > testing this extension we've consistently seen a condition where gRPC gets > into a state where any request that is made gets indefinitely stuck on the > epoll_wait syscall (or times out if a timeout is set on > grpc_completion_queue_next). Everything works fine and is chugging along > and then this problem happens and all of the requests get stuck/timeout. > This is what it looks like in gdb: > > Thread 21 (Thread 0x7f54f6bff700 (LWP 51033)): > > #0 0x00007f554ad90d43 in epoll_wait () from /lib64/libc.so.6 *<-- > indefinitely stuck or times out if one is set* > > #1 0x00007f55416969e5 in add_poll_object (exec_ctx=0x2482ad88, > bag=0x188924, bag_type=(POLL_OBJ_POLLSET | unknown: 32596), item=0x0, > item_type=(POLL_OBJ_POLLSET | unknown: 1097427428)) at > src/core/lib/iomgr/ev_epollsig_linux.c:1484 > > #2 0x00007f5541697972 in fd_ref (fd=0x4, reason=0x33b8b87c0 <Address > 0x33b8b87c0 out of bounds>, file=0x0, line=0) at > src/core/lib/iomgr/ev_poll_posix.c:447 > > #3 0x00007f55416a4691 in tcp_drop_uncovered_then_handle_write > (exec_ctx=0x7f54f6bf8680, arg=0x7f4c4e2c9010, error=0x0) at > src/core/lib/iomgr/tcp_posix.c:239 > > #4 0x00007f55416c71a8 in grpc_server_request_registered_call > (server=0x0, rmp=0x0, call=0x2482ad88, deadline=0x188924, > initial_metadata=0x7f4c4e2c8f00, optional_payload=0x0, > cq_bound_to_call=0x4, cq_for_notification=0x33b8b87c0, > > tag=0x0) at src/core/lib/surface/server.c:1486 > > > #5 0x00007f55416c75d2 in conforms_to (slice=..., > legal_bits=0x7f4c22ce2e50 "\270\064\245\214L\177", err_desc=0x7f54f6bf8701 > "\211\030") at src/core/lib/surface/validate_metadata.c:40 > > #6 0x00007f5541b97105 in HPHP::c_Call_ni_startBatch > (this_=0x7f4c22ce2e60, actions=...) at > /home/ryangordon/hhvm/grpc/src/php/ext/grpc/hhvm/call.cpp:529 > > > The stack trace doesn't always look like that but it always is stuck on > epoll_wait/epoll_pwait often from gpr_cv_wait. > > > I've managed to get GPRC_TRACE=all GRPC_VERBOSITY=DEBUG of a good request > and a request when it is in the bad state to compare side by side. > > > Good Request: > https://gist.githubusercontent.com/RyanGordon/831a8213e735bb1a4e5b93a854aab3c8/raw/7e37d595dbe56a77274bff83b64ab661a80e0c27/Not-Frozen%2520Log%2520Snippet > > Bad Request: > https://gist.githubusercontent.com/RyanGordon/831a8213e735bb1a4e5b93a854aab3c8/raw/7e37d595dbe56a77274bff83b64ab661a80e0c27/Frozen%2520log%2520snippet > > > The bad request looks like this when it's execution deviates: > > > D0919 14:54:36.312349629 51030 combiner.c:163] C:0x7f54faf35c00 > grpc_combiner_execute c=0x7f4c22edbfb0 last=61995 > D0919 14:54:36.312353011 51030 exec_ctx.c:73] closure > 0x7f4c22edbec0 finished > I0919 14:54:36.312358626 51030 completion_queue.c:834] > grpc_completion_queue_next(cq=0x7f4c22e9e200, deadline=gpr_timespec { tv_sec: > 4, tv_nsec: 999000000, clock_type: 3 }, reserved=(nil)) > > ... > > > Whereas, the good request does this: > > D0915 15:19:50.178995777 13689 combiner.c:163] C:0x7f932172f700 > grpc_combiner_execute c=0x7f9313d67fb0 last=1 > D0915 15:19:50.179005880 13689 exec_ctx.c:73] closure > 0x7f9313d67ec0 finished > D0915 15:19:50.179074826 13689 combiner.c:225] C:0x7f932172f700 > grpc_combiner_continue_exec_ctx contended=0 exec_ctx_ready_to_finish=1 > time_to_execute_final_list=0 > D0915 15:19:50.179077765 13689 combiner.c:243] C:0x7f932172f700 > maybe_finish_one n=0x7f9313d67fb0 > > ... (and a whole lot more) > > > > > Effectively it seems like the something is not getting scheduled when it > should be (grpc_combiner_continue_exec_ctx never gets run). I've been working > on this for a few weeks now and haven't been able to track down why or a fix. > I have the full logs if they might be helpful. I've been testing on my branch > that is kept pretty close to grpc/grpc master. > > > Does anyone have any idea what is going on? I have the bad process open on a > test server in gdb and have timeouts implemented so I can run repeated > requests at it to continue debugging if necessary. > > > Thanks, > > Ryan > > -- > You received this message because you are subscribed to the Google Groups " > grpc.io" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/grpc-io. > To view this discussion on the web visit > https://groups.google.com/d/msgid/grpc-io/b3cc406f-9b93-4259-b8f9-df3eb904132a%40googlegroups.com > <https://groups.google.com/d/msgid/grpc-io/b3cc406f-9b93-4259-b8f9-df3eb904132a%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "grpc.io" group. 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