KCSAN: data-race in sctp_do_sm / sctp_wait_for_connect

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b96fbd602d35 Merge tag 's390-6.0-4' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=102c44e8880000
kernel config: https://syzkaller.appspot.com/x/.config?x=b0e266e64576e711
dashboard link: https://syzkaller.appspot.com/bug?extid=b44132eee91ea2c878a6
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
CC: [da...@davemloft.net edum...@google.com ku...@kernel.org linux-...@vger.kernel.org linux...@vger.kernel.org marcelo...@gmail.com net...@vger.kernel.org nho...@tuxdriver.com pab...@redhat.com vyas...@gmail.com]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/94300ae1e75d/disk-b96fbd60.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/733ecb1082ef/vmlinux-b96fbd60.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b44132...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in sctp_do_sm / sctp_wait_for_connect

write to 0xffff88813989b228 of 4 bytes by task 7418 on cpu 0:
sctp_cmd_new_state net/sctp/sm_sideeffect.c:872 [inline]
sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1334 [inline]
sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline]
sctp_do_sm+0xcfe/0x2ed0 net/sctp/sm_sideeffect.c:1170
sctp_primitive_SHUTDOWN+0x71/0x80 net/sctp/primitive.c:89
sctp_close+0x277/0x550 net/sctp/socket.c:1526
inet_release+0xc6/0xe0 net/ipv4/af_inet.c:428
__sock_release net/socket.c:650 [inline]
sock_close+0x6c/0x150 net/socket.c:1365
__fput+0x292/0x510 fs/file_table.c:320
____fput+0x11/0x20 fs/file_table.c:353
task_work_run+0x8e/0x110 kernel/task_work.c:177
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0x124/0x130 kernel/entry/common.c:169
exit_to_user_mode_prepare kernel/entry/common.c:201 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
syscall_exit_to_user_mode+0x6a/0x90 kernel/entry/common.c:294
do_syscall_64+0x37/0x70 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88813989b228 of 4 bytes by task 7401 on cpu 1:
sctp_wait_for_connect+0x14f/0x360 net/sctp/socket.c:9298
sctp_sendmsg_to_asoc+0xb7d/0xb90 net/sctp/socket.c:1879
sctp_sendmsg+0x1280/0x1840 net/sctp/socket.c:2025
inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
__sys_sendto+0x22d/0x2d0 net/socket.c:2117
__do_sys_sendto net/socket.c:2129 [inline]
__se_sys_sendto net/socket.c:2125 [inline]
__x64_sys_sendto+0x74/0x90 net/socket.c:2125
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7401 Comm: syz-executor.2 Not tainted 6.0.0-rc4-syzkaller-00302-gb96fbd602d35-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.