=============================
WARNING: suspicious RCU usage
5.7.0-rc4-syzkaller #0 Not tainted
-----------------------------
include/linux/radix-tree.h:167 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/u4:5/1057:
 #0: ffff88821b077938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:226 [inline]
 #0: ffff88821b077938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff88821b077938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
 #0: ffff88821b077938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
 #0: ffff88821b077938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline]
 #0: ffff88821b077938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline]
 #0: ffff88821b077938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: process_one_work+0x814/0x15d0 kernel/workqueue.c:2239
 #1: ffffc90004527e00 ((work_completion)(&qrtr_ns.work)){+.+.}-{0:0}, at: process_one_work+0x849/0x15d0 kernel/workqueue.c:2243

stack backtrace:
CPU: 0 PID: 1057 Comm: kworker/u4:5 Not tainted 5.7.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: qrtr_ns_handler qrtr_ns_worker
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x128/0x182 lib/dump_stack.c:118
 radix_tree_deref_slot include/linux/radix-tree.h:167 [inline]
 ctrl_cmd_new_lookup+0x595/0x680 net/qrtr/ns.c:558
 qrtr_ns_worker+0x272/0x10d7 net/qrtr/ns.c:674
 process_one_work+0x908/0x15d0 kernel/workqueue.c:2268
 worker_thread+0x82/0xb50 kernel/workqueue.c:2414
 kthread+0x340/0x410 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification
failed to send lookup notification