=============================== [ INFO: suspicious RCU usage. ] 4.9.205-syzkaller #0 Not tainted ------------------------------- include/linux/inetdevice.h:205 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 4 locks held by syz-executor.3/25954: #0: (rcu_read_lock_bh){......}, at: [<00000000ec67351f>] ip_finish_output2+0x20b/0x1280 net/ipv4/ip_output.c:198 #1: (rcu_read_lock_bh){......}, at: [<0000000001b05f7b>] __dev_queue_xmit+0x1d4/0x1bd0 net/core/dev.c:3407 #2: (_xmit_TUNNEL6#2){+.-...}, at: [<0000000078a56904>] spin_lock include/linux/spinlock.h:302 [inline] #2: (_xmit_TUNNEL6#2){+.-...}, at: [<0000000078a56904>] __netif_tx_lock include/linux/netdevice.h:3573 [inline] #2: (_xmit_TUNNEL6#2){+.-...}, at: [<0000000078a56904>] __dev_queue_xmit+0x1116/0x1bd0 net/core/dev.c:3469 #3: (slock-AF_INET){+.-...}, at: [<00000000d6ec10f3>] spin_trylock include/linux/spinlock.h:312 [inline] #3: (slock-AF_INET){+.-...}, at: [<00000000d6ec10f3>] icmp_xmit_lock net/ipv4/icmp.c:220 [inline] #3: (slock-AF_INET){+.-...}, at: [<00000000d6ec10f3>] __icmp_send+0x48b/0x1420 net/ipv4/icmp.c:656 stack backtrace: CPU: 1 PID: 25954 Comm: syz-executor.3 Not tainted 4.9.205-syzkaller #0 ffff8801adf9edd8 ffffffff81b55e6b ffff8801a6c3f8c0 0000000000000000 0000000000000002 00000000000000cd ffff8801ae442f80 ffff8801adf9ee08 ffffffff81406997 ffff8801a6c3f918 ffff8801adf9ef28 ffff8801d7716600 Call Trace: [<000000004bedf060>] __dump_stack lib/dump_stack.c:15 [inline] [<000000004bedf060>] dump_stack+0xcb/0x130 lib/dump_stack.c:56 [<000000007c972c45>] lockdep_rcu_suspicious.cold+0x10a/0x149 kernel/locking/lockdep.c:4458 [<00000000a7fad2bc>] __in_dev_get_rcu include/linux/inetdevice.h:205 [inline] [<00000000a7fad2bc>] fib_compute_spec_dst+0x6c4/0xcc0 net/ipv4/fib_frontend.c:284 input: syz1 as /devices/virtual/input/input84 [<00000000725ff4cc>] __ip_options_echo+0x4be/0x13e0 net/ipv4/ip_options.c:177 [<00000000a0c9683f>] __icmp_send+0x648/0x1420 net/ipv4/icmp.c:685 [<00000000c52aa6d3>] ipv4_send_dest_unreach net/ipv4/route.c:1203 [inline] [<00000000c52aa6d3>] ipv4_link_failure+0x460/0x850 net/ipv4/route.c:1210 [<000000003378873d>] dst_link_failure include/net/dst.h:490 [inline] [<000000003378873d>] vti6_xmit net/ipv6/ip6_vti.c:522 [inline] [<000000003378873d>] vti6_tnl_xmit+0xb08/0x17f0 net/ipv6/ip6_vti.c:561 [<000000002d21ea4a>] __netdev_start_xmit include/linux/netdevice.h:4072 [inline] [<000000002d21ea4a>] netdev_start_xmit include/linux/netdevice.h:4081 [inline] [<000000002d21ea4a>] xmit_one net/core/dev.c:2977 [inline] [<000000002d21ea4a>] dev_hard_start_xmit+0x195/0x8b0 net/core/dev.c:2993 [<00000000f92b5e2e>] __dev_queue_xmit+0x11a3/0x1bd0 net/core/dev.c:3473 [<000000005cbe2024>] dev_queue_xmit+0x18/0x20 net/core/dev.c:3506 [<00000000dea4d697>] neigh_direct_output+0x16/0x20 net/core/neighbour.c:1368 [<0000000005ef5d0f>] dst_neigh_output include/net/dst.h:470 [inline] [<0000000005ef5d0f>] ip_finish_output2+0x6a2/0x1280 net/ipv4/ip_output.c:225 [<0000000010bdbaed>] ip_finish_output+0x3c4/0xce0 net/ipv4/ip_output.c:313 [<000000006a1528f5>] NF_HOOK_COND include/linux/netfilter.h:246 [inline] [<000000006a1528f5>] ip_output+0x1ec/0x5b0 net/ipv4/ip_output.c:401 [<0000000050cfb0af>] dst_output include/net/dst.h:507 [inline] [<0000000050cfb0af>] NF_HOOK_THRESH include/linux/netfilter.h:232 [inline] [<0000000050cfb0af>] NF_HOOK include/linux/netfilter.h:255 [inline] [<0000000050cfb0af>] raw_send_hdrinc net/ipv4/raw.c:421 [inline] [<0000000050cfb0af>] raw_sendmsg+0x1c5c/0x23e0 net/ipv4/raw.c:643 [<0000000050a05246>] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:766 [<0000000040c1d4f9>] sock_sendmsg_nosec net/socket.c:649 [inline] [<0000000040c1d4f9>] sock_sendmsg+0xbe/0x110 net/socket.c:659 [<00000000c550aacd>] sock_write_iter+0x235/0x3d0 net/socket.c:857 [<000000000ae8b621>] new_sync_write fs/read_write.c:498 [inline] [<000000000ae8b621>] __vfs_write+0x3c1/0x560 fs/read_write.c:511 [<0000000097eba5c2>] vfs_write+0x185/0x520 fs/read_write.c:559 [<0000000081237299>] SYSC_write fs/read_write.c:607 [inline] [<0000000081237299>] SyS_write+0x121/0x270 fs/read_write.c:599 [<0000000001c4d3ba>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<00000000b3d963c2>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb input: syz1 as /devices/virtual/input/input85 input: syz1 as /devices/virtual/input/input86 input: syz1 as /devices/virtual/input/input87 input: syz1 as /devices/virtual/input/input88 input: syz1 as /devices/virtual/input/input89 input: syz1 as /devices/virtual/input/input90 input: syz1 as /devices/virtual/input/input91 input: syz1 as /devices/virtual/input/input92 input: syz1 as /devices/virtual/input/input93 input: syz1 as /devices/virtual/input/input95 input: syz1 as /devices/virtual/input/input94 input: syz1 as /devices/virtual/input/input96 input: syz1 as /devices/virtual/input/input97 audit_printk_skb: 36 callbacks suppressed audit: type=1400 audit(2000000978.769:2348): avc: denied { create } for pid=26147 comm="syz-executor.5" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1 audit: type=1400 audit(2000000979.529:2349): avc: denied { create } for pid=26174 comm="syz-executor.2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1 FAT-fs (loop5): bogus number of reserved sectors FAT-fs (loop5): Can't find a valid FAT filesystem FAT-fs (loop5): bogus number of reserved sectors FAT-fs (loop5): Can't find a valid FAT filesystem