=============================== [ INFO: suspicious RCU usage. ] 4.9.124-g6a1b592 #34 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 syz-executor6/9489: #0: (sb_writers#5){.+.+.+}, at: [] file_start_write include/linux/fs.h:2640 [inline] #0: (sb_writers#5){.+.+.+}, at: [] do_sendfile+0x918/0xc60 fs/read_write.c:1392 #1: (&sb->s_type->i_mutex_key#11){++++++}, at: [] inode_lock include/linux/fs.h:766 [inline] #1: (&sb->s_type->i_mutex_key#11){++++++}, at: [] generic_file_write_iter+0x9d/0x610 mm/filemap.c:2903 #2: (rcu_read_lock){......}, at: [] find_get_entry+0x0/0x540 include/linux/compiler.h:243 #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: 9489 Comm: syz-executor6 Not tainted 4.9.124-g6a1b592 #34 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801db207d60 ffffffff81eb95e9 ffff880196f2e000 0000000000000000 0000000000000002 ffffffff83c6e380 ffff8801acf883d8 ffff8801db207d90 ffffffff81428551 ffff8801acf88280 ffff8801d701cc48 ffff8801d701c448 Call Trace: [ 483.326513] [] __dump_stack lib/dump_stack.c:15 [inline] [ 483.326513] [] 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+0x210/0x940 kernel/softirq.c:288 [] invoke_softirq kernel/softirq.c:368 [inline] [] irq_exit+0x114/0x150 kernel/softirq.c:409 [] exiting_irq arch/x86/include/asm/apic.h:669 [inline] [] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:962 [] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648 [ 483.441628] [] ? rcu_read_unlock include/linux/rcupdate.h:930 [inline] [ 483.441628] [] ? find_get_entry+0x120/0x540 mm/filemap.c:1130 [] rcu_read_unlock include/linux/rcupdate.h:930 [inline] [] find_get_entry+0x125/0x540 mm/filemap.c:1130 [] find_lock_entry+0x31/0x3e0 mm/filemap.c:1157 [] shmem_getpage_gfp+0x178/0x1de0 mm/shmem.c:1582 [] shmem_getpage mm/shmem.c:123 [inline] [] shmem_write_begin+0xfb/0x1a0 mm/shmem.c:2203 [] generic_perform_write+0x301/0x510 mm/filemap.c:2753 [] __generic_file_write_iter+0x352/0x540 mm/filemap.c:2878 [] generic_file_write_iter+0x2e0/0x610 mm/filemap.c:2906 [] vfs_iter_write+0x2e0/0x460 fs/read_write.c:390 [] iter_file_splice_write+0x5fb/0xb30 fs/splice.c:768 [] do_splice_from fs/splice.c:870 [inline] [] direct_splice_actor+0x128/0x190 fs/splice.c:1037 [] splice_direct_to_actor+0x2c1/0x7e0 fs/splice.c:992 [] do_splice_direct+0x1a3/0x270 fs/splice.c:1080 [] do_sendfile+0x4f0/0xc60 fs/read_write.c:1393 [] C_SYSC_sendfile fs/read_write.c:1469 [inline] [] compat_SyS_sendfile+0xd1/0x160 fs/read_write.c:1458 [] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline] [] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387 [] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137 ODEBUG: object ffff8801db207ce8 is NOT on stack ffff8801cb4a8000, but annotated ------------[ cut here ]------------ WARNING: CPU: 0 PID: 9489 at lib/debugobjects.c:303 debug_object_is_on_stack lib/debugobjects.c:303 [inline] WARNING: CPU: 0 PID: 9489 at lib/debugobjects.c:303 __debug_object_init.cold.10+0x6b/0x2b0 lib/debugobjects.c:329