Received signal Aborted (6) because grpc assertion failed.

stack:

2879586 2021.06.21 03:45:06.442175 [ 2251376 ] <Error> grpc: /tmp/tzg/release-centos7/prepare-environments/grpc/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc, line number : 290, log msg : assertion failed: subchannel_list() == p->subchannel_list_.get() || subchannel_list() == p->latest_pending_subchannel_list_.get()
2879630 2021.06.21 03:45:06.500475 [ 2251377 ] <Error> BaseDaemon: (from thread 2251376) Received signal Aborted (6).
2879736 2021.06.21 03:45:06.602214 [ 2251377 ] <Error> BaseDaemon: 0. /lib64/libc.so.6(gsignal+0x37) [0x7f689c5ce207]
2879737 2021.06.21 03:45:06.602295 [ 2251377 ] <Error> BaseDaemon: 1. /lib64/libc.so.6(abort+0x148) [0x7f689c5cf8f8]
2879768 2021.06.21 03:45:06.642060 [ 2251377 ] <Error> BaseDaemon: 2. bin/tiflash/tiflash() [0x831cb20]
2879802 2021.06.21 03:45:06.664835 [ 2251377 ] <Error> BaseDaemon: 3. bin/tiflash/tiflash() [0x826fc32]
2879803 2021.06.21 03:45:06.664889 [ 2251377 ] <Error> BaseDaemon: 4. bin/tiflash/tiflash(grpc_combiner_continue_exec_ctx()+0x86) [0x828f0b6]
2879804 2021.06.21 03:45:06.664908 [ 2251377 ] <Error> BaseDaemon: 5. bin/tiflash/tiflash(grpc_core::ExecCtx::Flush()+0x73) [0x822d0b3]
2879805 2021.06.21 03:45:06.664927 [ 2251377 ] <Error> BaseDaemon: 6. bin/tiflash/tiflash(grpc_core::Executor::RunClosures(char const*, grpc_closure_list)+0xa2) [0x822d362]
2879806 2021.06.21 03:45:06.664944 [ 2251377 ] <Error> BaseDaemon: 7. bin/tiflash/tiflash(grpc_core::Executor::ThreadMain(void*)+0x172) [0x822d542]
2879807 2021.06.21 03:45:06.664960 [ 2251377 ] <Error> BaseDaemon: 8. bin/tiflash/tiflash() [0x85a9043]
2879808 2021.06.21 03:45:06.664976 [ 2251377 ] <Error> BaseDaemon: 9. /lib64/libpthread.so.0(+0x7dd5) [0x7f689cc6edd5]

version:
5.0.1 + hotfix
branch: release5.0-hotfix-tiflash-patch3
commit: e9218d

Start by reproducing the abort on release5.0-hotfix-tiflash-patch3 at commit e9218d and inspect the grpc pick_first.cc assertion shown in the stack. Trace the subchannel-list state through the grpc combiner execution path; done means identifying a reproducible cause and verifying a fix with a regression test or equivalent reproduction.