syzbot


KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv (7)

Status: moderation: reported on 2026/01/05 19:04
Subsystems: tipc
[Documentation on labels]
Reported-by: syzbot+c2554c7622dd36deb461@syzkaller.appspotmail.com
First crash: 11d, last: 5d07h
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv tipc 6 1 926d 926d 0/29 auto-obsoleted due to no activity on 2023/08/04 11:38
upstream KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv (2) tipc 6 1 566d 566d 0/29 auto-obsoleted due to no activity on 2024/07/29 09:10
upstream KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv (6) tipc 6 1 124d 124d 0/29 auto-obsoleted due to no activity on 2025/11/04 10:56
upstream KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv (4) tipc 6 3 272d 221d 0/29 auto-obsoleted due to no activity on 2025/06/18 09:51
upstream KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv (3) tipc 6 1 522d 522d 0/29 auto-obsoleted due to no activity on 2024/09/11 16:33
upstream KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv (5) tipc 6 1 193d 193d 0/29 auto-obsoleted due to no activity on 2025/08/27 14:35

Sample crash report:
==================================================================
BUG: KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv

read-write to 0xffff888103b28c26 of 2 bytes by task 2454 on cpu 1:
 tipc_sk_conn_proto_rcv net/tipc/socket.c:1367 [inline]
 tipc_sk_proto_rcv+0x66e/0xb00 net/tipc/socket.c:2156
 tipc_sk_filter_rcv+0x18ea/0x1a00 net/tipc/socket.c:2350
 tipc_sk_enqueue net/tipc/socket.c:2443 [inline]
 tipc_sk_rcv+0x4dc/0x18b0 net/tipc/socket.c:2495
 tipc_node_xmit+0x18b/0x890 net/tipc/node.c:1701
 tipc_node_xmit_skb+0x91/0xc0 net/tipc/node.c:1766
 tipc_sk_send_ack+0x25c/0x270 net/tipc/socket.c:1824
 tipc_recvmsg+0x809/0x9d0 net/tipc/socket.c:1992
 sock_recvmsg_nosec net/socket.c:1078 [inline]
 sock_recvmsg+0x139/0x170 net/socket.c:1100
 tipc_conn_rcv_from_sock net/tipc/topsrv.c:401 [inline]
 tipc_conn_recv_work+0x13d/0x280 net/tipc/topsrv.c:424
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff888103b28c26 of 2 bytes by task 2390 on cpu 0:
 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_arm_poll_handler+0x1ee/0xb70 io_uring/poll.c:581
 io_arm_apoll+0x2e8/0x420 io_uring/poll.c:689
 io_arm_poll_handler+0x131/0x160 io_uring/poll.c:718
 io_queue_async+0x25d/0x2d0 io_uring/io_uring.c:2024
 io_queue_sqe io_uring/io_uring.c:2050 [inline]
 io_submit_sqe io_uring/io_uring.c:2321 [inline]
 io_submit_sqes+0xb90/0x11b0 io_uring/io_uring.c:2435
 __do_sys_io_uring_enter io_uring/io_uring.c:3285 [inline]
 __se_sys_io_uring_enter+0x1bd/0x1a30 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+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0208 -> 0x0186

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2390 Comm: syz.5.12829 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/06 19:10 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv
2025/12/31 11:12 upstream c8ebd433459b d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv
2025/12/31 11:09 upstream c8ebd433459b d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in tipc_poll / tipc_sk_proto_rcv
* Struck through repros no longer work on HEAD.