============================= WARNING: suspicious RCU usage 5.9.0-rc4-syzkaller #0 Not tainted ----------------------------- include/linux/radix-tree.h:176 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/u4:3/42: #0: ffff8880a9145138 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a9145138 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8880a9145138 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8880a9145138 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8880a9145138 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8880a9145138 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc90000f07da8 ((work_completion)(&qrtr_ns.work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 stack backtrace: CPU: 0 PID: 42 Comm: kworker/u4:3 Not tainted 5.9.0-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+0x198/0x1fd lib/dump_stack.c:118 radix_tree_deref_slot include/linux/radix-tree.h:176 [inline] radix_tree_deref_slot include/linux/radix-tree.h:174 [inline] ctrl_cmd_new_lookup+0x6d4/0x7c0 net/qrtr/ns.c:558 qrtr_ns_worker+0x5a9/0x14fc net/qrtr/ns.c:674 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 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 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 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 failed to send lookup notification