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BUG: KCSAN: data-race in sctp_association_free / sctp_wait_for_connect

write to 0xffff88809b73701c of 1 bytes by task 18220 on cpu 1:
 sctp_association_free+0x153/0x560 net/sctp/associola.c:336
 sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:930 [inline]
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1318 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1185 [inline]
 sctp_do_sm+0x2a29/0x3120 net/sctp/sm_sideeffect.c:1156
 sctp_primitive_SHUTDOWN+0x71/0x80 net/sctp/primitive.c:89
 sctp_sendmsg_check_sflags+0x159/0x1c0 net/sctp/socket.c:1751
 sctp_sendmsg+0x11d6/0x1a90 net/sctp/socket.c:2004
 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:817
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2353
 ___sys_sendmsg net/socket.c:2407 [inline]
 __sys_sendmmsg+0x322/0x4b0 net/socket.c:2497
 __do_sys_sendmmsg net/socket.c:2526 [inline]
 __se_sys_sendmmsg net/socket.c:2523 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2523
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88809b73701c of 1 bytes by task 18215 on cpu 0:
 sctp_wait_for_connect+0x168/0x300 net/sctp/socket.c:9050
 __sctp_connect+0x94f/0xa50 net/sctp/socket.c:1230
 __sctp_setsockopt_connectx net/sctp/socket.c:1319 [inline]
 sctp_setsockopt_connectx net/sctp/socket.c:1346 [inline]
 sctp_setsockopt+0x2d87/0x7f90 net/sctp/socket.c:4487
 sock_common_setsockopt+0x5d/0x70 net/core/sock.c:3247
 __sys_setsockopt+0x2dc/0x450 net/socket.c:2132
 __do_sys_setsockopt net/socket.c:2143 [inline]
 __se_sys_setsockopt net/socket.c:2140 [inline]
 __x64_sys_setsockopt+0x62/0x70 net/socket.c:2140
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18215 Comm: syz-executor.3 Not tainted 5.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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