=============================== [ INFO: suspicious RCU usage. ] 4.9.113-g47bbcd6 #62 Not tainted ------------------------------- kernel/rcu/tree_plugin.h:678 Illegal synchronize_rcu() in RCU read-side critical section! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 4 locks held by modprobe/10777: #0: (&mm->mmap_sem){++++++}, at: [] __do_page_fault+0x36b/0xd50 arch/x86/mm/fault.c:1336 #1: (rcu_read_lock){......}, at: [] filemap_map_pages+0xfa/0xd40 mm/filemap.c:2229 #2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [] spin_lock include/linux/spinlock.h:302 [inline] #2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [] pte_alloc_one_map mm/memory.c:2906 [inline] #2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [] alloc_set_pte+0xb98/0x11d0 mm/memory.c:3004 #3: (rcu_callback){......}, at: [] __rcu_reclaim kernel/rcu/rcu.h:108 [inline] #3: (rcu_callback){......}, at: [] rcu_do_batch kernel/rcu/tree.c:2789 [inline] #3: (rcu_callback){......}, at: [] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline] #3: (rcu_callback){......}, at: [] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline] #3: (rcu_callback){......}, at: [] rcu_process_callbacks+0x98e/0x12b0 kernel/rcu/tree.c:3037 stack backtrace: CPU: 0 PID: 10777 Comm: modprobe Not tainted 4.9.113-g47bbcd6 #62 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801db207d60 ffffffff81eb32a9 ffff8801b6590000 0000000000000000 0000000000000002 ffffffff83c6df20 ffff8801b65312d8 ffff8801db207d90 ffffffff814260f0 ffff8801b6531180 ffff8801c37e8848 ffff8801c37e8048 Call Trace: [ 135.289849] [] __dump_stack lib/dump_stack.c:15 [inline] [ 135.289849] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] lockdep_rcu_suspicious.cold.48+0x110/0x141 kernel/locking/lockdep.c:4455 [] synchronize_rcu+0x68/0x90 kernel/rcu/tree_plugin.h:675 [] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1796 [] l2tp_tunnel_closeall+0x1f7/0x350 net/l2tp/l2tp_core.c:1364 [] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1324 [] __sk_destruct+0x55/0x590 net/core/sock.c:1428 [] __rcu_reclaim kernel/rcu/rcu.h:118 [inline] [] rcu_do_batch kernel/rcu/tree.c:2789 [inline] [] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline] [] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline] [] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037 [] __do_softirq+0x20b/0x937 kernel/softirq.c:284 [] invoke_softirq kernel/softirq.c:364 [inline] [] irq_exit+0x147/0x190 kernel/softirq.c:405 [] exiting_irq arch/x86/include/asm/apic.h:659 [inline] [] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:960 [] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648 [ 135.404208] [] ? filemap_map_pages+0x8ee/0xd40 mm/filemap.c:2281 [] do_fault_around mm/memory.c:3129 [inline] [] do_read_fault mm/memory.c:3169 [inline] [] do_fault mm/memory.c:3309 [inline] [] handle_pte_fault mm/memory.c:3510 [inline] [] __handle_mm_fault mm/memory.c:3597 [inline] [] handle_mm_fault+0x1cb3/0x28e0 mm/memory.c:3634 [] __do_page_fault+0x5af/0xd50 arch/x86/mm/fault.c:1407 [] do_page_fault+0x27/0x30 arch/x86/mm/fault.c:1470 [] page_fault+0x28/0x30 arch/x86/entry/entry_64.S:951 ODEBUG: object ffff8801db207ce8 is NOT on stack ffff8801a1d20000, but annotated ------------[ cut here ]------------ WARNING: CPU: 0 PID: 10777 at lib/debugobjects.c:303 debug_object_is_on_stack lib/debugobjects.c:303 [inline] WARNING: CPU: 0 PID: 10777 at lib/debugobjects.c:303 __debug_object_init.cold.10+0x6b/0x2b0 lib/debugobjects.c:329