Hello, While running syzkaller fuzzer I've got the following deadlock report: ================================= [ INFO: inconsistent lock state ] 4.7.0-rc5+ #28 Not tainted --------------------------------- inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. syz-executor/354 [HC0[0]:SC0[0]:HE1:SE1] takes: (slock-AF_INET){+.?...}, at: [< inline >] spin_lock include/linux/spinlock.h:302 (slock-AF_INET){+.?...}, at: [<ffffffff864831b1>] dccp_v4_ctl_send_reset+0xac1/0x10d0 net/dccp/ipv4.c:530 {IN-SOFTIRQ-W} state was registered at: [< inline >] mark_irqflags kernel/locking/lockdep.c:2915 [<ffffffff814791ec>] __lock_acquire+0xb5c/0x2fb0 kernel/locking/lockdep.c:3287 [<ffffffff8147c293>] lock_acquire+0x1e3/0x460 kernel/locking/lockdep.c:3741 [< inline >] __raw_spin_lock include/linux/spinlock_api_smp.h:144 [<ffffffff86a93f83>] _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151 [< inline >] spin_lock include/linux/spinlock.h:302 [<ffffffff85cf22a5>] udp_queue_rcv_skb+0x4d5/0x18d0 net/ipv4/udp.c:1597 [<ffffffff85cf3d72>] __udp4_lib_rcv+0x6d2/0x3270 net/ipv4/udp.c:1770 [<ffffffff85cf78c1>] udp_rcv+0x21/0x30 net/ipv4/udp.c:1962 [<ffffffff85c1de10>] ip_local_deliver_finish+0x2b0/0xa30 net/ipv4/ip_input.c:216 [< inline >] NF_HOOK_THRESH include/linux/netfilter.h:219 [< inline >] NF_HOOK include/linux/netfilter.h:242 [<ffffffff85c1ec82>] ip_local_deliver+0x1b2/0x350 net/ipv4/ip_input.c:257 [< inline >] dst_input include/net/dst.h:507 [<ffffffff85c1c73d>] ip_rcv_finish+0x6fd/0x1b20 net/ipv4/ip_input.c:395 [< inline >] NF_HOOK_THRESH include/linux/netfilter.h:219 [< inline >] NF_HOOK include/linux/netfilter.h:242 [<ffffffff85c1f7e9>] ip_rcv+0x9c9/0x1150 net/ipv4/ip_input.c:486 [<ffffffff8590f5ee>] __netif_receive_skb_core+0x180e/0x28b0 net/core/dev.c:4205 [<ffffffff859106ba>] __netif_receive_skb+0x2a/0x170 net/core/dev.c:4243 [<ffffffff85913545>] netif_receive_skb_internal+0x1b5/0x390 net/core/dev.c:4271 [< inline >] napi_skb_finish net/core/dev.c:4599 [<ffffffff8591818e>] napi_gro_receive+0x2de/0x500 net/core/dev.c:4631 [<ffffffff83ed3f73>] e1000_clean_rx_irq+0x4e3/0x1160 drivers/net/ethernet/intel/e1000e/netdev.c:1028 [<ffffffff83ed5a46>] e1000_clean+0xa16/0x24e0 drivers/net/ethernet/intel/e1000/e1000_main.c:3836 [< inline >] napi_poll net/core/dev.c:5135 [<ffffffff8591560d>] net_rx_action+0x7ed/0xf10 net/core/dev.c:5200 [<ffffffff86a97ebc>] __do_softirq+0x25c/0xa50 kernel/softirq.c:273 [< inline >] invoke_softirq kernel/softirq.c:350 [<ffffffff81381cef>] irq_exit+0x18f/0x1d0 kernel/softirq.c:391 [< inline >] exiting_irq ./arch/x86/include/asm/apic.h:658 [<ffffffff86a976fb>] smp_apic_timer_interrupt+0x7b/0xa0 arch/x86/kernel/apic/apic.c:932 [<ffffffff86a95a6c>] apic_timer_interrupt+0x8c/0xa0 arch/x86/entry/entry_64.S:451 [<ffffffff83729a6b>] class_dev_iter_next+0x8b/0xd0 drivers/base/class.c:324 [<ffffffff8372a761>] class_find_device+0x101/0x1c0 drivers/base/class.c:428 [< inline >] tty_get_device drivers/tty/tty_io.c:3134 [<ffffffff83105a56>] alloc_tty_struct+0x5f6/0x840 drivers/tty/tty_io.c:3178 [<ffffffff83105d18>] tty_init_dev+0x78/0x4b0 drivers/tty/tty_io.c:1528 [<ffffffff83121053>] ptmx_open+0xf3/0x310 drivers/tty/pty.c:753 [<ffffffff8181aa1e>] chrdev_open+0x22e/0x4c0 fs/char_dev.c:392 [<ffffffff81806218>] do_dentry_open+0x698/0xca0 fs/open.c:736 [<ffffffff818097cf>] vfs_open+0x10f/0x210 fs/open.c:849 [< inline >] do_last fs/namei.c:3360 [<ffffffff8183e999>] path_openat+0x12f9/0x2a80 fs/namei.c:3483 [<ffffffff8184372c>] do_filp_open+0x18c/0x250 fs/namei.c:3518 [<ffffffff81809fcc>] do_sys_open+0x1fc/0x420 fs/open.c:1016 [< inline >] SYSC_open fs/open.c:1034 [<ffffffff8180a21d>] SyS_open+0x2d/0x40 fs/open.c:1029 [<ffffffff86a94e00>] entry_SYSCALL_64_fastpath+0x23/0xc1 arch/x86/entry/entry_64.S:207 irq event stamp: 201 hardirqs last enabled at (201): [< inline >] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:162 hardirqs last enabled at (201): [<ffffffff86a94b51>] _raw_spin_unlock_irqrestore+0x31/0xc0 kernel/locking/spinlock.c:191 hardirqs last disabled at (200): [< inline >] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 hardirqs last disabled at (200): [<ffffffff86a949f8>] _raw_spin_lock_irqsave+0x78/0xd0 kernel/locking/spinlock.c:159 softirqs last enabled at (170): [< inline >] spin_unlock_bh include/linux/spinlock.h:352 softirqs last enabled at (170): [<ffffffff858b426c>] __release_sock+0xcc/0x3a0 net/core/sock.c:2051 softirqs last disabled at (168): [< inline >] spin_lock_bh include/linux/spinlock.h:307 softirqs last disabled at (168): [<ffffffff858b43fe>] __release_sock+0x25e/0x3a0 net/core/sock.c:2065 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(slock-AF_INET); <Interrupt> lock(slock-AF_INET); *** DEADLOCK *** 1 lock held by syz-executor/354: #0: (sk_lock-AF_INET){+.+.+.}, at: [< inline >] lock_sock include/net/sock.h:1388 #0: (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff85d193f4>] inet_stream_connect+0x44/0xa0 net/ipv4/af_inet.c:660 stack backtrace: CPU: 3 PID: 354 Comm: syz-executor Not tainted 4.7.0-rc5+ #28 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffffffff880b58e0 ffff8800361378c0 ffffffff82cc01af ffffffff00000000 fffffbfff1016b1c ffff88003abfe840 ffffffff899bb700 ffff88003abff0a8 ffffffff86cae460 0000000000000001 ffff880036137930 ffffffff8147684d Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffff82cc01af>] dump_stack+0x12e/0x18f lib/dump_stack.c:51 [<ffffffff8147684d>] print_usage_bug+0x34d/0x3a0 kernel/locking/lockdep.c:2383 [< inline >] valid_state kernel/locking/lockdep.c:2396 [< inline >] mark_lock_irq kernel/locking/lockdep.c:2594 [<ffffffff8147748c>] mark_lock+0xbec/0xe80 kernel/locking/lockdep.c:3057 [< inline >] mark_irqflags kernel/locking/lockdep.c:2933 [<ffffffff814793ce>] __lock_acquire+0xd3e/0x2fb0 kernel/locking/lockdep.c:3287 [<ffffffff8147c293>] lock_acquire+0x1e3/0x460 kernel/locking/lockdep.c:3741 [< inline >] __raw_spin_lock include/linux/spinlock_api_smp.h:144 [<ffffffff86a93f83>] _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151 [< inline >] spin_lock include/linux/spinlock.h:302 [<ffffffff864831b1>] dccp_v4_ctl_send_reset+0xac1/0x10d0 net/dccp/ipv4.c:530 [<ffffffff864838b9>] dccp_v4_do_rcv+0xf9/0x190 net/dccp/ipv4.c:684 [< inline >] sk_backlog_rcv include/net/sock.h:872 [<ffffffff858b42c7>] __release_sock+0x127/0x3a0 net/core/sock.c:2058 [<ffffffff858b4599>] release_sock+0x59/0x1c0 net/core/sock.c:2516 [<ffffffff85d19428>] inet_stream_connect+0x78/0xa0 net/ipv4/af_inet.c:662 [<ffffffff858a62ae>] SYSC_connect+0x23e/0x2e0 net/socket.c:1536 [<ffffffff858ab3d4>] SyS_connect+0x24/0x30 net/socket.c:1517 [<ffffffff86a94e00>] entry_SYSCALL_64_fastpath+0x23/0xc1 arch/x86/entry/entry_64.S:207 On commit 1a0a02d1efa066001fd315c1b4df583d939fa2c4 (Jun 30). -- To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html