do_sys_recvmmsg+0xe4/0x190 net/socket.c:2472 __do_sys_recvmmsg net/socket.c:2485 [inline] __se_sys_recvmmsg net/socket.c:2481 [inline] __x64_sys_recvmmsg+0xbe/0x150 net/socket.c:2481 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 ============================================ WARNING: possible recursive locking detected 4.17.0-rc1+ #7 Not tainted entry_SYSCALL_64_after_hwframe+0x49/0xbe -------------------------------------------- RIP: 0033:0x455329 syz-executor7/11681 is trying to acquire lock: RSP: 002b:00007f0ac29edc68 EFLAGS: 00000246 00000000c874f149 ORIG_RAX: 000000000000012b ( RAX: ffffffffffffffda RBX: 00007f0ac29ee6d4 RCX: 0000000000455329 rtnl_mutex RDX: 0000000000000003 RSI: 00000000200000c0 RDI: 0000000000000013 ){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 RBP: 000000000072bea0 R08: 0000000020001c40 R09: 0000000000000000 but task is already holding lock: R10: 0000000040012000 R11: 0000000000000246 R12: 0000000000000014 00000000c874f149 R13: 0000000000000495 R14: 00000000006f9e98 R15: 0000000000000000 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(rtnl_mutex); lock(rtnl_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz-executor7/11681: #0: 00000000c874f149 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 #1: 0000000088a48399 (ipvs->sync_mutex){+.+.}, at: do_ip_vs_set_ctl+0x562/0x1d30 net/netfilter/ipvs/ip_vs_ctl.c:2388 stack backtrace: CPU: 1 PID: 11681 Comm: syz-executor7 Not tainted 4.17.0-rc1+ #7 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 print_deadlock_bug kernel/locking/lockdep.c:1761 [inline] check_deadlock kernel/locking/lockdep.c:1805 [inline] validate_chain kernel/locking/lockdep.c:2401 [inline] __lock_acquire.cold.62+0x18c/0x55b kernel/locking/lockdep.c:3431 lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16d/0x17f0 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 ip_mc_drop_socket+0x8f/0x270 net/ipv4/igmp.c:2643 inet_release+0x4e/0x1f0 net/ipv4/af_inet.c:413 sock_release+0x96/0x1b0 net/socket.c:594 start_sync_thread+0xdc3/0x2d40 net/netfilter/ipvs/ip_vs_sync.c:1924 do_ip_vs_set_ctl+0x59c/0x1d30 net/netfilter/ipvs/ip_vs_ctl.c:2389 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x7d/0xd0 net/netfilter/nf_sockopt.c:115 ip_setsockopt+0xd8/0xf0 net/ipv4/ip_sockglue.c:1253 tcp_setsockopt+0x93/0xe0 net/ipv4/tcp.c:2888 sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:3039 __sys_setsockopt+0x1bd/0x390 net/socket.c:1903 __do_sys_setsockopt net/socket.c:1914 [inline] __se_sys_setsockopt net/socket.c:1911 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1911 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455329 RSP: 002b:00007f6427fc3c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007f6427fc46d4 RCX: 0000000000455329 RDX: 000000000000048b RSI: 0000000000000000 RDI: 0000000000000016 RBP: 000000000072bf58 R08: 0000000000000018 R09: 0000000000000000 R10: 0000000020000080 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000520 R14: 00000000006faba0 R15: 0000000000000001 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 0 PID: 11679 Comm: syz-executor5 Not tainted 4.17.0-rc1+ #7 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.4+0xa/0x1a lib/fault-inject.c:149 __should_failslab+0x124/0x180 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1522 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc mm/slab.c:3378 [inline] __do_kmalloc mm/slab.c:3716 [inline] __kmalloc+0x2c8/0x760 mm/slab.c:3727 kmalloc include/linux/slab.h:517 [inline] kzalloc include/linux/slab.h:701 [inline] evdev_open+0x146/0x610 drivers/input/evdev.c:506 chrdev_open+0x256/0x760 fs/char_dev.c:417 do_dentry_open+0x7ef/0xf10 fs/open.c:784 vfs_open+0x139/0x230 fs/open.c:906 do_last fs/namei.c:3365 [inline] path_openat+0x1676/0x4e20 fs/namei.c:3501 do_filp_open+0x249/0x350 fs/namei.c:3535 do_sys_open+0x56f/0x740 fs/open.c:1093 __do_sys_open fs/open.c:1111 [inline] __se_sys_open fs/open.c:1106 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1106 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x40f581 RSP: 002b:00007fb81db057a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: cccccccccccccccd RCX: 000000000040f581 RDX: 0000000000000000 RSI: 0000000000004000 RDI: 00007fb81db05850 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000200001c0 R11: 0000000000000293 R12: 0000000000000014 R13: 0000000000000680 R14: 00000000006fcca0 R15: 0000000000000003