WARNING: suspicious RCU usage in ip6_pkt_drop

Status: closed as invalid on 2026/08/06 18:42
Subsystems: net
Labels: prio:high
[Documentation on labels]
First crash: 14d, last: 14d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
789729ee assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ✅ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING: suspicious RCU usage in ip6_pkt_drop 2026/07/30 00:00 2026/07/30 00:00 2026/07/30 01:12 2377cd3d

Sample crash report:
=============================
WARNING: suspicious RCU usage
syzkaller #0 Not tainted
-----------------------------
./include/net/addrconf.h:389 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by kworker/1:1/42:
 #0: ffff88801b02b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff88801b02b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffffc90000b27c40 ((work_completion)(&trans->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffffc90000b27c40 ((work_completion)(&trans->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405

stack backtrace:
CPU: 1 UID: 0 PID: 42 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events xfrm_trans_reinject
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 lockdep_rcu_suspicious+0x13f/0x1d0 kernel/locking/lockdep.c:6876
 __in6_dev_get_safely include/net/addrconf.h:389 [inline]
 ip6_pkt_drop+0x596/0x610 net/ipv6/route.c:4620
 ip6_pkt_discard+0x1c/0x30 net/ipv6/route.c:4651
 xfrm_trans_reinject+0x324/0x630 net/xfrm/xfrm_input.c:806
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/28 19:30 net e095f249e220 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING: suspicious RCU usage in ip6_pkt_drop
2026/07/28 13:52 net 9c88929cc18c 45ae1df4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING: suspicious RCU usage in ip6_pkt_drop
* Struck through repros no longer work on HEAD.