[moderation] [tipc?] KCSAN: data-race in __tipc_sendstream / tipc_poll (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c8ebd433459b Merge tag 'nfsd-6.19-2' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10338a9a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b319ff1b6a2797ca
dashboard link: https://syzkaller.appspot.com/bug?extid=c9ba86847ecac1751d2a
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [da...@davemloft.net edum...@google.com ho...@kernel.org jma...@redhat.com ku...@kernel.org linux-...@vger.kernel.org net...@vger.kernel.org pab...@redhat.com tipc-di...@lists.sourceforge.net]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d4c0e188b92f/disk-c8ebd433.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/25522cdc5fa6/vmlinux-c8ebd433.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a1499d747012/bzImage-c8ebd433.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c9ba86...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __tipc_sendstream / tipc_poll

read-write to 0xffff8881040358e6 of 2 bytes by task 5169 on cpu 0:
__tipc_sendstream+0x7e1/0xb20 net/tipc/socket.c:1628
tipc_sendstream+0x3e/0x60 net/tipc/socket.c:1546
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x145/0x180 net/socket.c:742
sock_write_iter+0x1a7/0x1f0 net/socket.c:1195
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x52a/0x960 fs/read_write.c:686
ksys_write+0xda/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+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881040358e6 of 2 bytes by task 5165 on cpu 1:
tsk_conn_cong net/tipc/socket.c:222 [inline]
tipc_poll+0x1f9/0x350 net/tipc/socket.c:806
sock_poll+0x20d/0x230 net/socket.c:1443
vfs_poll include/linux/poll.h:82 [inline]
io_poll_check_events io_uring/poll.c:280 [inline]
io_poll_task_func+0x127/0x760 io_uring/poll.c:336
io_handle_tw_list+0x122/0x230 io_uring/io_uring.c:1121
tctx_task_work_run+0x42/0x160 io_uring/io_uring.c:1181
tctx_task_work+0x3f/0x80 io_uring/io_uring.c:1199
task_work_run+0x131/0x1a0 kernel/task_work.c:233
get_signal+0xe12/0xf70 kernel/signal.c:2807
arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x6a/0x740 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x1e1/0x2b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x01c7 -> 0x0208

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5165 Comm: syz.1.11632 Tainted: G W syzkaller #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================


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