Redis [CRASH] unfinished module timer causes crash after the module unload

Crash report

=== REDIS BUG REPORT START: Cut & paste starting from here ===
13777:M 26 Jan 2022 15:31:51.542 # Redis 255.255.255 crashed by signal: 11, si_code: 1
13777:M 26 Jan 2022 15:31:51.542 # Accessing address: 0x10a3366a0
13777:M 26 Jan 2022 15:31:51.542 # Killed by PID: 0, UID: 0
13777:M 26 Jan 2022 15:31:51.542 # Crashed running the instruction at: 0x10a3366a0

------ STACK TRACE ------
EIP:
0   ???                                 0x000000010a3366a0 0x0 + 4466108064

Backtrace:
0   libsystem_platform.dylib            0x00007ff807f5be2d _sigtramp + 29
1   ???                                 0x00007ff7b5f6afd0 0x0 + 140701886492624
2   redis-server                        0x0000000109f993b6 aeProcessEvents + 1062
3   redis-server                        0x0000000109f9950d aeMain + 29
4   redis-server                        0x0000000109faad92 main + 2082
5   dyld                                0x000000011060f4fe start + 462

------ REGISTERS ------
13777:M 26 Jan 2022 15:31:51.542 #
RAX:0000000000000000 RBX:00007ff7b5f6b4b0
RCX:000000010a13a438 RDX:00000000000c67c7
RDI:00007ff7b5f6b438 RSI:000060000251cfc0
RBP:00007ff7b5f6b6c0 RSP:00007ff7b5f6b428
R8 :000004265aaa5a31 R9 :0000000003ac62cb
R10:0000000000000001 R11:00001ff7b346345c
R12:00007ff7b5f6b438 R13:00007ff7b5f6b4b0
R14:0000600002b16e00 R15:0005d67731fb0d63
RIP:000000010a3366a0 EFL:0000000000010246
CS :000000000000002b FS:0000000000000000  GS:0000000000000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b437) -> 0000000110340947
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b436) -> 0000000000000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b435) -> 0000000000000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b434) -> 0000000000000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b433) -> 0000000000000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b432) -> 0000000000000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b431) -> 0000000000000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b430) -> 0000000000000040
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b42f) -> 0000000000000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b42e) -> 0000000000000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b42d) -> 0000000000000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b42c) -> 00007fe903025400
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b42b) -> 0000600000f14060
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b42a) -> 000000010a03c4e0
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b429) -> 0000000a00000000
13777:M 26 Jan 2022 15:31:51.542 # (00007ff7b5f6b428) -> 000000010a0460fa

How to reproduce this issue 1. Under redis source folder, launch the Redis server 2. Load the timer module, module load tests/modules/timer.so 3. Launch a timer like 5 seconds. test.createtimer 5000 timer-incr-key 4. Meanwhile, unload the timer module, module unload timer 5. After about 5 seconds, the Redis crashs.