syzbot


KCSAN: data-race in nci_dev_up / nci_req_complete (5)

Status: moderation: reported on 2026/01/08 10:47
Subsystems: net nfc
[Documentation on labels]
Reported-by: syzbot+43e35be410f8b1d6a72d@syzkaller.appspotmail.com
First crash: 8d22h, last: 8d22h
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in nci_dev_up / nci_req_complete (2) nfc net 6 1 807d 807d 0/29 auto-obsoleted due to no activity on 2023/12/02 10:14
upstream KCSAN: data-race in nci_dev_up / nci_req_complete net nfc 6 1 921d 921d 0/29 auto-obsoleted due to no activity on 2023/08/11 03:41
upstream KCSAN: data-race in nci_dev_up / nci_req_complete (4) net nfc 6 2 673d 673d 0/29 auto-obsoleted due to no activity on 2024/04/14 23:38
upstream KCSAN: data-race in nci_dev_up / nci_req_complete (3) net nfc 6 2 736d 750d 0/29 auto-obsoleted due to no activity on 2024/02/11 16:39

Sample crash report:
==================================================================
BUG: KCSAN: data-race in nci_dev_up / nci_req_complete

write to 0xffff88811bfb69a0 of 4 bytes by task 6091 on cpu 1:
 __nci_request net/nfc/nci/core.c:136 [inline]
 nci_open_device net/nfc/nci/core.c:503 [inline]
 nci_dev_up+0x272/0x8f0 net/nfc/nci/core.c:632
 nfc_dev_up+0x103/0x1b0 net/nfc/core.c:118
 nfc_genl_dev_up+0x53/0x90 net/nfc/netlink.c:775
 genl_family_rcv_msg_doit+0x143/0x1b0 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x422/0x460 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x145/0x180 net/socket.c:742
 ____sys_sendmsg+0x31e/0x4a0 net/socket.c:2592
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2646
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2683 [inline]
 __se_sys_sendmsg net/socket.c:2681 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2681
 x64_sys_call+0x17ba/0x3000 arch/x86/include/generated/asm/syscalls_64.h:47
 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 0xffff88811bfb69a0 of 4 bytes by task 2331 on cpu 0:
 nci_req_complete+0x23/0x90 net/nfc/nci/core.c:80
 nci_rsp_packet+0xc6f/0xe30 net/nfc/nci/rsp.c:-1
 nci_rx_work+0x16f/0x2c0 net/nfc/nci/core.c:1551
 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

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2331 Comm: kworker/u8:13 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: nfc2_nci_rx_wq nci_rx_work
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/04 10:42 upstream aacb0a6d604a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in nci_dev_up / nci_req_complete
* Struck through repros no longer work on HEAD.