TiFlash crash for the null pointer access

Bug Report

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1. Minimal reproduce step (Required)

[2022/11/14 08:40:46.735 +08:00] [ERROR] [BaseDaemon.cpp:377] [########################################] [source=BaseDaemon] [thread_id=7684]
[2022/11/14 08:40:46.735 +08:00] [ERROR] [BaseDaemon.cpp:378] ["(from thread 7683) Received signal Segmentation fault(11)."] [source=BaseDaemon] [thread_id=7684]
[2022/11/14 08:40:46.736 +08:00] [ERROR] [BaseDaemon.cpp:406] ["Address: NULL pointer."] [source=BaseDaemon] [thread_id=7684]
[2022/11/14 08:40:46.736 +08:00] [ERROR] [BaseDaemon.cpp:414] ["Access: read."] [source=BaseDaemon] [thread_id=7684]
[2022/11/14 08:40:46.736 +08:00] [ERROR] [BaseDaemon.cpp:426] ["Unknown si_code."] [source=BaseDaemon] [thread_id=7684]
[2022/11/14 08:40:46.767 +08:00] [ERROR] [BaseDaemon.cpp:570] ["\n       0x5544c01\tfaultSignalHandler(int, siginfo_t*, void*) [tiflash+89410561]\n                \tlibs/libdaemon/src/BaseDaemon.cpp:221\n  0x7fa37a025630\t<unknown symbol> [libpthread.so.0+63024]\n       0x69b6913\ttimer_thread(void*) [tiflash+110848275]\n                \tcontrib/grpc/src/core/lib/iomgr/timer_manager.cc:284\n       0x6c8bdca\tgrpc_core::(anonymous namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void (*)(void*), void*, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::__invoke(void*) [tiflash+113819082]\n                \tcontrib/grpc/src/core/lib/gprpp/thd_posix.cc:110\n  0x7fa37a01dea5\tstart_thread [libpthread.so.0+32421]"] [source=BaseDaemon] [thread_id=7684]

2. What did you expect to see? (Required)

3. What did you see instead (Required)

4. What is your TiFlash version? (Required)

master 6b393836ea60e5695692e59644e2f9f6aaa81c07

Start with the stack trace in libs/libdaemon/src/BaseDaemon.cpp:221 and contrib/grpc/src/core/lib/iomgr/timer_manager.cc:284, then inspect the related thread code in thd_posix.cc:110. Reproduce the segmentation fault if possible and trace the NULL read to its source; done means the crash is prevented and the behavior is covered by an appropriate regression test.