[ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.61' (ECDSA) to the list of known hosts. syzkaller login: [ 44.807034][ T6893] IPVS: ftp: loaded support on port[0] = 21 [ 44.899136][ T21] [ 44.901676][ T21] ============================= [ 44.906546][ T21] WARNING: suspicious RCU usage [ 44.912620][ T21] 5.7.0-syzkaller #0 Not tainted [ 44.917582][ T21] ----------------------------- [ 44.923518][ T21] include/linux/radix-tree.h:176 suspicious rcu_dereference_check() usage! [ 44.932638][ T21] [ 44.932638][ T21] other info that might help us debug this: [ 44.932638][ T21] [ 44.943639][ T21] [ 44.943639][ T21] rcu_scheduler_active = 2, debug_locks = 1 [ 44.952112][ T21] 2 locks held by kworker/u4:1/21: [ 44.957209][ T21] #0: ffff88821b097938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: process_one_work+0x6df/0xfd0 [ 44.968300][ T21] #1: ffffc90000dd7d80 ((work_completion)(&qrtr_ns.work)){+.+.}-{0:0}, at: process_one_work+0x71e/0xfd0 [ 44.979598][ T21] [ 44.979598][ T21] stack backtrace: [ 44.985503][ T21] CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.7.0-syzkaller #0 [ 44.993361][ T21] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.003397][ T21] Workqueue: qrtr_ns_handler qrtr_ns_worker [ 45.009311][ T21] Call Trace: [ 45.012589][ T21] dump_stack+0x1e9/0x30e [ 45.016901][ T21] qrtr_ns_worker+0x2aff/0x4500 [ 45.021738][ T21] ? __lock_acquire+0x116c/0x2c30 [ 45.026768][ T21] process_one_work+0x76e/0xfd0 [ 45.031626][ T21] worker_thread+0xa7f/0x1450 [ 45.036289][ T21] kthread+0x353/0x380 [ 45.040332][ T21] ? rcu_lock_release+0x20/0x20 [ 45.045155][ T21] ? kthread_blkcg+0xd0/0xd0 [