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KCSAN: data-race in rxrpc_peer_keepalive_worker / rxrpc_send_data_packet

Status: upstream: reported on 2026/01/07 15:34
Subsystems: afs net
[Documentation on labels]
Reported-by: syzbot+6182afad5045e6703b3d@syzkaller.appspotmail.com
First crash: 46d, last: 46d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [afs?] [net?] KCSAN: data-race in rxrpc_peer_keepalive_worker / rxrpc_send_data_packet 3 (4) 2026/01/08 14:28

Sample crash report:
==================================================================
BUG: KCSAN: data-race in rxrpc_peer_keepalive_worker / rxrpc_send_data_packet

write to 0xffff8881044ab560 of 8 bytes by task 4063 on cpu 1:
 rxrpc_send_data_packet+0x1593/0x1df0 net/rxrpc/output.c:714
 rxrpc_transmit_fresh_data net/rxrpc/call_event.c:255 [inline]
 rxrpc_transmit_some_data+0x63c/0x8b0 net/rxrpc/call_event.c:277
 rxrpc_input_call_event+0x8bb/0xf30 net/rxrpc/call_event.c:401
 rxrpc_io_thread+0x1c1e/0x21c0 net/rxrpc/io_thread.c:550
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x122/0x1b0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff8881044ab560 of 8 bytes by task 3500 on cpu 0:
 rxrpc_peer_keepalive_dispatch net/rxrpc/peer_event.c:268 [inline]
 rxrpc_peer_keepalive_worker+0x44e/0x800 net/rxrpc/peer_event.c:341
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3346
 worker_thread+0x582/0x770 kernel/workqueue.c:3427
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x122/0x1b0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000000000000 -> 0x0000000000000029

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3500 Comm: kworker/u9:1 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: krxrpcd rxrpc_peer_keepalive_worker
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/26 21:30 upstream 30f09200cc4a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rxrpc_peer_keepalive_worker / rxrpc_send_data_packet
* Struck through repros no longer work on HEAD.