syzbot

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BUG: KCSAN: data-race in __tipc_sendstream / tipc_poll

read-write to 0xffff88810b1dbf26 of 2 bytes by task 5741 on cpu 0:
 __tipc_sendstream+0x804/0xb60 net/tipc/socket.c:1628
 tipc_sendstream+0x3e/0x60 net/tipc/socket.c:1546
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x145/0x170 net/socket.c:742
 sock_write_iter+0x1d2/0x210 net/socket.c:1195
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5a6/0x9f0 fs/read_write.c:686
 ksys_write+0xdc/0x1a0 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:746
 x64_sys_call+0x2847/0x3000 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810b1dbf26 of 2 bytes by task 5738 on cpu 1:
 tsk_conn_cong net/tipc/socket.c:222 [inline]
 tipc_poll+0x1f9/0x340 net/tipc/socket.c:806
 sock_poll+0x21c/0x240 net/socket.c:1443
 vfs_poll include/linux/poll.h:82 [inline]
 __io_arm_poll_handler+0x1ee/0xb60 io_uring/poll.c:581
 io_poll_add+0x69/0xf0 io_uring/poll.c:899
 __io_issue_sqe+0xfd/0x2d0 io_uring/io_uring.c:1793
 io_issue_sqe+0x56/0xa70 io_uring/io_uring.c:1816
 io_queue_sqe io_uring/io_uring.c:2043 [inline]
 io_submit_sqe io_uring/io_uring.c:2321 [inline]
 io_submit_sqes+0x78a/0x11b0 io_uring/io_uring.c:2435
 __do_sys_io_uring_enter io_uring/io_uring.c:3285 [inline]
 __se_sys_io_uring_enter+0x1bf/0x1c70 io_uring/io_uring.c:3224
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3224
 x64_sys_call+0x27e4/0x3000 arch/x86/include/generated/asm/syscalls_64.h:427
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0082 -> 0x00c3

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5738 Comm: syz.3.833 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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