netlink: 'syz.6.9466': attribute type 21 has an invalid length.
==================================================================
BUG: KCSAN: data-race in sctp_do_sm / sctp_wait_for_connect

write to 0xffff88810292b228 of 4 bytes by task 30243 on cpu 0:
 sctp_cmd_new_state net/sctp/sm_sideeffect.c:878 [inline]
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1342 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1204 [inline]
 sctp_do_sm+0x9b9/0x3230 net/sctp/sm_sideeffect.c:1175
 sctp_primitive_SHUTDOWN+0x74/0x90 net/sctp/primitive.c:89
 sctp_close+0x272/0x550 net/sctp/socket.c:1528
 inet_release+0xce/0xf0 net/ipv4/af_inet.c:437
 __sock_release net/socket.c:662 [inline]
 sock_close+0x6b/0x150 net/socket.c:1455
 __fput+0x29b/0x650 fs/file_table.c:468
 ____fput+0x1c/0x30 fs/file_table.c:496
 task_work_run+0x131/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xed/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810292b228 of 4 bytes by task 30237 on cpu 1:
 sctp_wait_for_connect+0x153/0x370 net/sctp/socket.c:9328
 sctp_sendmsg_to_asoc+0xf0b/0xf20 net/sctp/socket.c:1885
 sctp_sendmsg+0x1263/0x18d0 net/sctp/socket.c:2031
 inet_sendmsg+0xc5/0xd0 net/ipv4/af_inet.c:853
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x102/0x180 net/socket.c:742
 __sys_sendto+0x268/0x330 net/socket.c:2244
 __do_sys_sendto net/socket.c:2251 [inline]
 __se_sys_sendto net/socket.c:2247 [inline]
 __x64_sys_sendto+0x76/0x90 net/socket.c:2247
 x64_sys_call+0x2d14/0x3000 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 30237 Comm: syz.6.9466 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
==================================================================