[moderation] [tipc?] KCSAN: data-race in tipc_group_cong / tipc_poll

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7cdabafc0012 Merge tag 'trace-v6.15-rc1' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1459cdac580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a84f9483dff14ac4
dashboard link: https://syzkaller.appspot.com/bug?extid=1fc2a4efb72afd941651
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
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/7e5d47443d4d/disk-7cdabafc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8b1f81770f02/vmlinux-7cdabafc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/10c36bb14c0c/bzImage-7cdabafc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1fc2a4...@syzkaller.appspotmail.com

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

write to 0xffff888110f71ff8 of 1 bytes by task 19441 on cpu 0:
tipc_group_cong+0x191/0x2b0 net/tipc/group.c:434
tipc_group_bc_cong+0xeb/0x110 net/tipc/group.c:467
tipc_send_group_bcast+0x1d6/0x700 net/tipc/socket.c:1097
__tipc_sendmsg+0x1a0/0x1c90 net/tipc/socket.c:-1
tipc_sendmsg+0x3e/0x60 net/tipc/socket.c:1399
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0x140/0x180 net/socket.c:727
____sys_sendmsg+0x350/0x4e0 net/socket.c:2566
___sys_sendmsg net/socket.c:2620 [inline]
__sys_sendmmsg+0x22a/0x4b0 net/socket.c:2709
__do_sys_sendmmsg net/socket.c:2736 [inline]
__se_sys_sendmmsg net/socket.c:2733 [inline]
__x64_sys_sendmmsg+0x57/0x70 net/socket.c:2733
x64_sys_call+0x2b53/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:308
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888110f71ff8 of 1 bytes by task 19437 on cpu 1:
tipc_poll+0x11e/0x360 net/tipc/socket.c:815
sock_poll+0x22d/0x250 net/socket.c:1379
vfs_poll include/linux/poll.h:82 [inline]
select_poll_one fs/select.c:480 [inline]
do_select+0x92b/0xfc0 fs/select.c:536
core_sys_select+0x4c3/0x6d0 fs/select.c:677
do_pselect fs/select.c:759 [inline]
__do_sys_pselect6 fs/select.c:802 [inline]
__se_sys_pselect6+0x212/0x270 fs/select.c:793
__x64_sys_pselect6+0x78/0x90 fs/select.c:793
x64_sys_call+0x1c26/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:271
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 19437 Comm: syz.3.5829 Not tainted 6.15.0-rc1-syzkaller-00325-g7cdabafc0012 #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


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[syzbot]

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