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    SubjectRe: net/netlink: null-ptr-deref in netlink_dump/lock_acquire
    On Thu, Nov 3, 2016 at 6:21 PM, Andrey Konovalov <andreyknvl@google.com> wrote:
    > Hi,
    >
    > Another report that looks related:
    >
    > [ INFO: possible circular locking dependency detected ]
    > 4.9.0-rc3+ #344 Not tainted
    > -------------------------------------------------------
    > syz-executor/25526 is trying to acquire lock:
    > ([ 950.351060] &table[i].mutex
    > [<ffffffff82dcf798>] nfnl_lock+0x28/0x30 net/netfilter/nfnetlink.c:61
    >
    > but task is already holding lock:
    > ([ 950.351060] rtnl_mutex
    > [< inline >] rtnl_lock net/core/rtnetlink.c:70
    > [<ffffffff82c15efb>] rtnetlink_rcv+0x1b/0x40 net/core/rtnetlink.c:4032
    >
    > which lock already depends on the new lock.
    >
    >
    > the existing dependency chain (in reverse order) is:
    >
    > :
    > [ 950.351060] [<ffffffff8120c52e>] lock_acquire+0x17e/0x340
    > kernel/locking/lockdep.c:3746
    > [ 950.351060] [< inline >] __mutex_lock_common
    > kernel/locking/mutex.c:521
    > [ 950.351060] [<ffffffff83fb7221>]
    > mutex_lock_nested+0xb1/0x890 kernel/locking/mutex.c:621
    > [ 950.351060] [<ffffffff82c11297>] rtnl_lock+0x17/0x20
    > net/core/rtnetlink.c:70
    > [ 950.351060] [<ffffffff839fe31f>]
    > nl80211_get_reg_dump+0x5f/0x400 net/wireless/nl80211.c:6171
    > [ 950.351060] [<ffffffff82dc18d8>] genl_lock_dumpit+0x68/0x90
    > net/netlink/genetlink.c:517
    > [ 950.351060] [<ffffffff82db6947>] netlink_dump+0x397/0xac0
    > net/netlink/af_netlink.c:2110
    > [ 950.351060] [<ffffffff82db99b1>]
    > __netlink_dump_start+0x501/0x770 net/netlink/af_netlink.c:2200
    > [ 950.351060] [<ffffffff82dc2cb8>]
    > genl_family_rcv_msg+0xad8/0xc80 net/netlink/genetlink.c:584
    > [ 950.351060] [<ffffffff82dc3016>] genl_rcv_msg+0x1b6/0x270
    > net/netlink/genetlink.c:658
    > [ 950.351060] [<ffffffff82dc10a0>] netlink_rcv_skb+0x2c0/0x3b0
    > net/netlink/af_netlink.c:2281
    > [ 950.351060] [<ffffffff82dc21c8>] genl_rcv+0x28/0x40
    > net/netlink/genetlink.c:669
    > [ 950.351060] [< inline >] netlink_unicast_kernel
    > net/netlink/af_netlink.c:1214
    > [ 950.351060] [<ffffffff82dbf959>] netlink_unicast+0x5a9/0x880
    > net/netlink/af_netlink.c:1240
    > [ 950.351060] [<ffffffff82dc05e7>] netlink_sendmsg+0x9b7/0xce0
    > net/netlink/af_netlink.c:1786
    > [ 950.351060] [< inline >] sock_sendmsg_nosec net/socket.c:606
    > [ 950.351060] [<ffffffff82b6f75c>] sock_sendmsg+0xcc/0x110
    > net/socket.c:616
    > [ 950.351060] [<ffffffff82b6f9c1>] sock_write_iter+0x221/0x3b0
    > net/socket.c:814
    > [ 950.351060] [< inline >] new_sync_write fs/read_write.c:499
    > [ 950.351060] [<ffffffff8151bd44>] __vfs_write+0x334/0x570
    > fs/read_write.c:512
    > [ 950.351060] [<ffffffff8151f85b>] vfs_write+0x17b/0x500
    > fs/read_write.c:560
    > [ 950.351060] [< inline >] SYSC_write fs/read_write.c:607
    > [ 950.351060] [<ffffffff81523184>] SyS_write+0xd4/0x1a0
    > fs/read_write.c:599
    > [ 950.351060] [<ffffffff83fc0281>] entry_SYSCALL_64_fastpath+0x1f/0xc2
    >
    > :
    > [ 950.351060] [<ffffffff8120c52e>] lock_acquire+0x17e/0x340
    > kernel/locking/lockdep.c:3746
    > [ 950.351060] [< inline >] __mutex_lock_common
    > kernel/locking/mutex.c:521
    > [ 950.351060] [<ffffffff83fb7221>]
    > mutex_lock_nested+0xb1/0x890 kernel/locking/mutex.c:621
    > [ 950.351060] [< inline >] genl_lock net/netlink/genetlink.c:31
    > [ 950.351060] [<ffffffff82dc18b1>] genl_lock_dumpit+0x41/0x90
    > net/netlink/genetlink.c:516
    > [ 950.351060] [<ffffffff82db6947>] netlink_dump+0x397/0xac0
    > net/netlink/af_netlink.c:2110
    > [ 950.351060] [<ffffffff82db99b1>]
    > __netlink_dump_start+0x501/0x770 net/netlink/af_netlink.c:2200
    > [ 950.351060] [<ffffffff82dc2cb8>]
    > genl_family_rcv_msg+0xad8/0xc80 net/netlink/genetlink.c:584
    > [ 950.351060] [<ffffffff82dc3016>] genl_rcv_msg+0x1b6/0x270
    > net/netlink/genetlink.c:658
    > [ 950.351060] [<ffffffff82dc10a0>] netlink_rcv_skb+0x2c0/0x3b0
    > net/netlink/af_netlink.c:2281
    > [ 950.351060] [<ffffffff82dc21c8>] genl_rcv+0x28/0x40
    > net/netlink/genetlink.c:669
    > [ 950.351060] [< inline >] netlink_unicast_kernel
    > net/netlink/af_netlink.c:1214
    > [ 950.351060] [<ffffffff82dbf959>] netlink_unicast+0x5a9/0x880
    > net/netlink/af_netlink.c:1240
    > [ 950.351060] [<ffffffff82dc05e7>] netlink_sendmsg+0x9b7/0xce0
    > net/netlink/af_netlink.c:1786
    > [ 950.351060] [< inline >] sock_sendmsg_nosec net/socket.c:606
    > [ 950.351060] [<ffffffff82b6f75c>] sock_sendmsg+0xcc/0x110
    > net/socket.c:616
    > [ 950.351060] [<ffffffff82b6f9c1>] sock_write_iter+0x221/0x3b0
    > net/socket.c:814
    > [ 950.351060] [< inline >] new_sync_write fs/read_write.c:499
    > [ 950.351060] [<ffffffff8151bd44>] __vfs_write+0x334/0x570
    > fs/read_write.c:512
    > [ 950.351060] [<ffffffff8151f85b>] vfs_write+0x17b/0x500
    > fs/read_write.c:560
    > [ 950.351060] [< inline >] SYSC_write fs/read_write.c:607
    > [ 950.351060] [<ffffffff81523184>] SyS_write+0xd4/0x1a0
    > fs/read_write.c:599
    > [ 950.351060] [<ffffffff83fc0281>] entry_SYSCALL_64_fastpath+0x1f/0xc2
    >
    > :
    > [ 950.351060] [<ffffffff8120c52e>] lock_acquire+0x17e/0x340
    > kernel/locking/lockdep.c:3746
    > [ 950.351060] [< inline >] __mutex_lock_common
    > kernel/locking/mutex.c:521
    > [ 950.351060] [<ffffffff83fb7221>]
    > mutex_lock_nested+0xb1/0x890 kernel/locking/mutex.c:621
    > [ 950.351060] [<ffffffff82db95aa>]
    > __netlink_dump_start+0xfa/0x770 net/netlink/af_netlink.c:2170
    > [ 950.351060] [< inline >] netlink_dump_start
    > include/linux/netlink.h:165
    > [ 950.351060] [<ffffffff82e19309>]
    > ctnetlink_stat_ct_cpu+0xd9/0x130
    > net/netfilter/nf_conntrack_netlink.c:2045
    > [ 950.351060] [<ffffffff82dd1d80>]
    > nfnetlink_rcv_msg+0xa10/0xc10 net/netfilter/nfnetlink.c:212
    > [ 950.351060] [<ffffffff82dc10a0>] netlink_rcv_skb+0x2c0/0x3b0
    > net/netlink/af_netlink.c:2281
    > [ 950.351060] [<ffffffff82dd07e8>] nfnetlink_rcv+0x848/0x1170
    > net/netfilter/nfnetlink.c:474
    > [ 950.351060] [< inline >] netlink_unicast_kernel
    > net/netlink/af_netlink.c:1214
    > [ 950.351060] [<ffffffff82dbf959>] netlink_unicast+0x5a9/0x880
    > net/netlink/af_netlink.c:1240
    > [ 950.351060] [<ffffffff82dc05e7>] netlink_sendmsg+0x9b7/0xce0
    > net/netlink/af_netlink.c:1786
    > [ 950.351060] [< inline >] sock_sendmsg_nosec net/socket.c:606
    > [ 950.351060] [<ffffffff82b6f75c>] sock_sendmsg+0xcc/0x110
    > net/socket.c:616
    > [ 950.351060] [<ffffffff82b6f9c1>] sock_write_iter+0x221/0x3b0
    > net/socket.c:814
    > [ 950.351060] [< inline >] new_sync_write fs/read_write.c:499
    > [ 950.351060] [<ffffffff8151bd44>] __vfs_write+0x334/0x570
    > fs/read_write.c:512
    > [ 950.351060] [<ffffffff8151f85b>] vfs_write+0x17b/0x500
    > fs/read_write.c:560
    > [ 950.351060] [< inline >] SYSC_write fs/read_write.c:607
    > [ 950.351060] [<ffffffff81523184>] SyS_write+0xd4/0x1a0
    > fs/read_write.c:599
    > [ 950.351060] [<ffffffff83fc0281>] entry_SYSCALL_64_fastpath+0x1f/0xc2
    >
    > :
    > [ 950.351060] [< inline >] check_prev_add
    > kernel/locking/lockdep.c:1829
    > [ 950.351060] [< inline >] check_prevs_add
    > kernel/locking/lockdep.c:1939
    > [ 950.351060] [< inline >] validate_chain
    > kernel/locking/lockdep.c:2266
    > [ 950.351060] [<ffffffff8120b0ca>]
    > __lock_acquire+0x2b4a/0x3450 kernel/locking/lockdep.c:3335
    > [ 950.351060] [<ffffffff8120c52e>] lock_acquire+0x17e/0x340
    > kernel/locking/lockdep.c:3746
    > [ 950.351060] [< inline >] __mutex_lock_common
    > kernel/locking/mutex.c:521
    > [ 950.351060] [<ffffffff83fb7221>]
    > mutex_lock_nested+0xb1/0x890 kernel/locking/mutex.c:621
    > [ 950.351060] [<ffffffff82dcf798>] nfnl_lock+0x28/0x30
    > net/netfilter/nfnetlink.c:61
    > [ 950.351060] [<ffffffff82e847bf>]
    > nf_tables_netdev_event+0x14f/0x590
    > net/netfilter/nf_tables_netdev.c:122
    > [ 950.351060] [<ffffffff8117c131>]
    > notifier_call_chain+0x91/0x1a0 kernel/notifier.c:93
    > [ 950.351060] [< inline >] __raw_notifier_call_chain
    > kernel/notifier.c:394
    > [ 950.351060] [<ffffffff8117c2bd>]
    > raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
    > [ 950.351060] [<ffffffff82bc3851>]
    > call_netdevice_notifiers_info+0x51/0x90 net/core/dev.c:1645
    > [ 950.351060] [< inline >] call_netdevice_notifiers
    > net/core/dev.c:1661
    > [ 950.351060] [<ffffffff82be77c7>] dev_change_name+0x5d7/0x920
    > net/core/dev.c:1204
    > [ 950.351060] [<ffffffff82c171dd>] do_setlink+0x83d/0x30d0
    > net/core/rtnetlink.c:1993
    > [ 950.351060] [<ffffffff82c19ce0>] rtnl_setlink+0x270/0x330
    > net/core/rtnetlink.c:2231
    > [ 950.351060] [<ffffffff82c254a4>]
    > rtnetlink_rcv_msg+0x274/0x700 net/core/rtnetlink.c:4027
    > [ 950.351060] [<ffffffff82dc10a0>] netlink_rcv_skb+0x2c0/0x3b0
    > net/netlink/af_netlink.c:2281
    > [ 950.351060] [<ffffffff82c15f0a>] rtnetlink_rcv+0x2a/0x40
    > net/core/rtnetlink.c:4033
    > [ 950.351060] [< inline >] netlink_unicast_kernel
    > net/netlink/af_netlink.c:1214
    > [ 950.351060] [<ffffffff82dbf959>] netlink_unicast+0x5a9/0x880
    > net/netlink/af_netlink.c:1240
    > [ 950.351060] [<ffffffff82dc05e7>] netlink_sendmsg+0x9b7/0xce0
    > net/netlink/af_netlink.c:1786
    > [ 950.351060] [< inline >] sock_sendmsg_nosec net/socket.c:606
    > [ 950.351060] [<ffffffff82b6f75c>] sock_sendmsg+0xcc/0x110
    > net/socket.c:616
    > [ 950.351060] [<ffffffff82b6f9c1>] sock_write_iter+0x221/0x3b0
    > net/socket.c:814
    > [ 950.351060] [< inline >] new_sync_write fs/read_write.c:499
    > [ 950.351060] [<ffffffff8151bd44>] __vfs_write+0x334/0x570
    > fs/read_write.c:512
    > [ 950.351060] [<ffffffff8151f85b>] vfs_write+0x17b/0x500
    > fs/read_write.c:560
    > [ 950.351060] [< inline >] SYSC_write fs/read_write.c:607
    > [ 950.351060] [<ffffffff81523184>] SyS_write+0xd4/0x1a0
    > fs/read_write.c:599
    > [ 950.351060] [<ffffffff81006465>] do_syscall_64+0x195/0x490
    > arch/x86/entry/common.c:280
    > [ 950.351060] [<ffffffff83fc0349>] return_from_SYSCALL_64+0x0/0x7a
    >
    > other info that might help us debug this:
    >
    > Chain exists of:
    >
    >
    > Possible unsafe locking scenario:
    >
    > CPU0 CPU1
    > ---- ----
    > lock([ 950.351060] rtnl_mutex
    > );
    > lock([ 950.351060] genl_mutex
    > );
    > lock([ 950.351060] rtnl_mutex
    > );
    > lock([ 950.351060] &table[i].mutex
    > );
    >
    > *** DEADLOCK ***
    >
    > 1 lock held by syz-executor/25526:
    > #0: [ 950.351060] (
    >
    > stack backtrace:
    > CPU: 0 PID: 25526 Comm: syz-executor Not tainted 4.9.0-rc3+ #344
    > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    > ffff8800692b6d30 ffffffff81b46934 ffffffff859bdf80 ffffffff859de740
    > ffffffff859b3870 1ffffffff0bade82 ffff8800692b6d80 ffffffff81204cfd
    > ffffffff859b3870 ffff88006859cca0 000000006859c480 ffff88006859cca0
    > Call Trace:
    > [< inline >] __dump_stack lib/dump_stack.c:15
    > [<ffffffff81b46934>] dump_stack+0xb3/0x10f lib/dump_stack.c:51
    > [<ffffffff81204cfd>] print_circular_bug+0x28d/0x350
    > kernel/locking/lockdep.c:1202
    > [< inline >] check_prev_add kernel/locking/lockdep.c:1829
    > [< inline >] check_prevs_add kernel/locking/lockdep.c:1939
    > [< inline >] validate_chain kernel/locking/lockdep.c:2266
    > [<ffffffff8120b0ca>] __lock_acquire+0x2b4a/0x3450 kernel/locking/lockdep.c:3335
    > [<ffffffff8120c52e>] lock_acquire+0x17e/0x340 kernel/locking/lockdep.c:3746
    > [< inline >] __mutex_lock_common kernel/locking/mutex.c:521
    > [<ffffffff83fb7221>] mutex_lock_nested+0xb1/0x890 kernel/locking/mutex.c:621
    > [<ffffffff82dcf798>] nfnl_lock+0x28/0x30 net/netfilter/nfnetlink.c:61
    > [<ffffffff82e847bf>] nf_tables_netdev_event+0x14f/0x590
    > net/netfilter/nf_tables_netdev.c:122
    > [<ffffffff8117c131>] notifier_call_chain+0x91/0x1a0 kernel/notifier.c:93
    > [< inline >] __raw_notifier_call_chain kernel/notifier.c:394
    > [<ffffffff8117c2bd>] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
    > [<ffffffff82bc3851>] call_netdevice_notifiers_info+0x51/0x90
    > net/core/dev.c:1645
    > [< inline >] call_netdevice_notifiers net/core/dev.c:1661
    > [<ffffffff82be77c7>] dev_change_name+0x5d7/0x920 net/core/dev.c:1204
    > [<ffffffff82c171dd>] do_setlink+0x83d/0x30d0 net/core/rtnetlink.c:1993
    > [<ffffffff82c19ce0>] rtnl_setlink+0x270/0x330 net/core/rtnetlink.c:2231
    > [<ffffffff82c254a4>] rtnetlink_rcv_msg+0x274/0x700 net/core/rtnetlink.c:4027
    > [<ffffffff82dc10a0>] netlink_rcv_skb+0x2c0/0x3b0 net/netlink/af_netlink.c:2281
    > [<ffffffff82c15f0a>] rtnetlink_rcv+0x2a/0x40 net/core/rtnetlink.c:4033
    > [< inline >] netlink_unicast_kernel net/netlink/af_netlink.c:1214
    > [<ffffffff82dbf959>] netlink_unicast+0x5a9/0x880 net/netlink/af_netlink.c:1240
    > [<ffffffff82dc05e7>] netlink_sendmsg+0x9b7/0xce0 net/netlink/af_netlink.c:1786
    > [< inline >] sock_sendmsg_nosec net/socket.c:606
    > [<ffffffff82b6f75c>] sock_sendmsg+0xcc/0x110 net/socket.c:616
    > [<ffffffff82b6f9c1>] sock_write_iter+0x221/0x3b0 net/socket.c:814
    > [< inline >] new_sync_write fs/read_write.c:499
    > [<ffffffff8151bd44>] __vfs_write+0x334/0x570 fs/read_write.c:512
    > [<ffffffff8151f85b>] vfs_write+0x17b/0x500 fs/read_write.c:560
    > [< inline >] SYSC_write fs/read_write.c:607
    > [<ffffffff81523184>] SyS_write+0xd4/0x1a0 fs/read_write.c:599
    > [<ffffffff81006465>] do_syscall_64+0x195/0x490 arch/x86/entry/common.c:280
    > [<ffffffff83fc0349>] entry_SYSCALL64_slow_path+0x25/0x25
    >
    > On Thu, Nov 3, 2016 at 4:08 AM, Andrey Konovalov <andreyknvl@google.com> wrote:
    >> Hi Eric,
    >>
    >> This fixes the second report, the first one is still there.
    >> Apparently these are two separate issues.
    >>
    >> For the second one:
    >> Tested-by: Andrey Konovalov <andreyknvl@google.com>
    >>
    >> Thanks for the fix!
    >>
    >> On Thu, Nov 3, 2016 at 3:58 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
    >>> On Thu, 2016-11-03 at 03:36 +0100, Andrey Konovalov wrote:
    >>>> On Thu, Nov 3, 2016 at 1:15 AM, Andrey Konovalov <andreyknvl@google.com> wrote:
    >>>> > On Wed, Oct 19, 2016 at 4:13 PM, Andrey Konovalov <andreyknvl@google.com> wrote:
    >>>> >> Hi,
    >>>> >>
    >>>> >> I've got the following error report while running the syzkaller fuzzer:
    >>>> >>
    >>>> >> kasan: CONFIG_KASAN_INLINE enabled
    >>>> >> kasan: GPF could be caused by NULL-ptr deref or user memory access
    >>>> >> general protection fault: 0000 [#1] SMP KASAN
    >>>> >> Modules linked in:
    >>>> >> CPU: 1 PID: 3933 Comm: syz-executor Not tainted 4.9.0-rc1+ #230
    >>>> >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    >>>> >> task: ffff88006b79d800 task.stack: ffff88006bbc0000
    >>>> >> RIP: 0010:[<ffffffff8120872d>] [<ffffffff8120872d>]
    >>>> >> __lock_acquire+0x12d/0x3450 kernel/locking/lockdep.c:3221
    >>>> >> RSP: 0018:ffff88006bbc7420 EFLAGS: 00010006
    >>>> >> RAX: 0000000000000046 RBX: dffffc0000000000 RCX: 0000000000000000
    >>>> >> RDX: 000000000000000c RSI: 0000000000000000 RDI: 0000000000000003
    >>>> >> RBP: ffff88006bbc75c0 R08: 0000000000000001 R09: 0000000000000000
    >>>> >> R10: 0000000000000000 R11: ffffffff85f42240 R12: ffff88006b79d800
    >>>> >> R13: ffffffff84bfe4e0 R14: 0000000000000001 R15: 0000000000000060
    >>>> >> FS: 00007fd9c41cc700(0000) GS:ffff88006cd00000(0000) knlGS:0000000000000000
    >>>> >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    >>>> >> CR2: 0000000000451f80 CR3: 00000000638f0000 CR4: 00000000000006e0
    >>>> >> Stack:
    >>>> >> 0000000000000000 ffff88006bbc0000 ffff88006bbc8000 0000000000000000
    >>>> >> 0000000000000002 ffff88006b79d800 0000000000000000 ffff88006bbc7f48
    >>>> >> ffffffff852adc60 0000000000000000 ffffffff852adc64 1ffffffff0b40135
    >>>> >> Call Trace:
    >>>> >> [<ffffffff8120c5ae>] lock_acquire+0x17e/0x340 kernel/locking/lockdep.c:3746
    >>>> >> [< inline >] __mutex_lock_common kernel/locking/mutex.c:521
    >>>> >> [<ffffffff83fb6fe1>] mutex_lock_nested+0xb1/0x890 kernel/locking/mutex.c:621
    >>>> >> [<ffffffff82db6fd0>] netlink_dump+0x50/0xac0 net/netlink/af_netlink.c:2067
    >>>> >> [<ffffffff82dba381>] __netlink_dump_start+0x501/0x770
    >>>> >> net/netlink/af_netlink.c:2200
    >>>> >> [<ffffffff82dc35b2>] genl_family_rcv_msg+0xa02/0xc80
    >>>> >> net/netlink/genetlink.c:595
    >>>> >> [<ffffffff82dc39e6>] genl_rcv_msg+0x1b6/0x270 net/netlink/genetlink.c:658
    >>>> >> [<ffffffff82dc1a70>] netlink_rcv_skb+0x2c0/0x3b0 net/netlink/af_netlink.c:2281
    >>>> >> [<ffffffff82dc2b98>] genl_rcv+0x28/0x40 net/netlink/genetlink.c:669
    >>>> >> [< inline >] netlink_unicast_kernel net/netlink/af_netlink.c:1214
    >>>> >> [<ffffffff82dc0329>] netlink_unicast+0x5a9/0x880 net/netlink/af_netlink.c:1240
    >>>> >> [<ffffffff82dc0fb7>] netlink_sendmsg+0x9b7/0xce0 net/netlink/af_netlink.c:1786
    >>>> >> [< inline >] sock_sendmsg_nosec net/socket.c:606
    >>>> >> [<ffffffff82b7075c>] sock_sendmsg+0xcc/0x110 net/socket.c:616
    >>>> >> [<ffffffff82b709c1>] sock_write_iter+0x221/0x3b0 net/socket.c:814
    >>>> >> [< inline >] new_sync_write fs/read_write.c:499
    >>>> >> [<ffffffff8151c944>] __vfs_write+0x334/0x570 fs/read_write.c:512
    >>>> >> [<ffffffff8152045b>] vfs_write+0x17b/0x500 fs/read_write.c:560
    >>>> >> [< inline >] SYSC_write fs/read_write.c:607
    >>>> >> [<ffffffff81523d84>] SyS_write+0xd4/0x1a0 fs/read_write.c:599
    >>>> >> [<ffffffff83fc0141>] entry_SYSCALL_64_fastpath+0x1f/0xc2
    >>>> >> arch/x86/entry/entry_64.S:209
    >>>> >> Code: 0f 1f 44 00 00 f6 c4 02 0f 85 24 0a 00 00 44 8b 35 c9 61 8b 03
    >>>> >> 45 85 f6 74 2c 4c 89 fa 48 bb 00 00 00 00 00 fc ff df 48 c1 ea 03 <80>
    >>>> >> 3c 1a 00 0f 85 04 2f 00 00 49 81 3f a0 dc 2a 85 41 be 00 00
    >>>> >> RIP [<ffffffff8120872d>] __lock_acquire+0x12d/0x3450
    >>>> >> kernel/locking/lockdep.c:3221
    >>>> >> RSP <ffff88006bbc7420>
    >>>> >> ---[ end trace 685b3c182bf7f25c ]---
    >>>> >>
    >>>> >> The reproducer is attached.
    >>>> >>
    >>>> >> On commit 1a1891d762d6e64daf07b5be4817e3fbb29e3c59 (Oct 18).
    >>>> >
    >>>> > (Adding more maintainers)
    >>>> >
    >>>> > Still seeing this on 0c183d92b20b5c84ca655b45ef57b3318b83eb9e (Oct 31).
    >>>>
    >>>> Here is another report that might be related:
    >>>>
    >>>> =====================================
    >>>> [ BUG: bad unlock balance detected! ]
    >>>> 4.9.0-rc3+ #336 Not tainted
    >>>> -------------------------------------
    >>>> syz-executor/4018 is trying to release lock ([ 36.220068] nl_table_lock
    >>>> ) at:
    >>>> [<ffffffff82dc8683>] netlink_diag_dump+0x1a3/0x250 net/netlink/diag.c:182
    >>>> but there are no more locks to release!
    >>>>
    >>>> other info that might help us debug this:
    >>>> 3 locks held by syz-executor/4018:
    >>>> #0: [ 36.220068] (
    >>>> sock_diag_mutex[ 36.220068] ){+.+.+.}
    >>>> , at: [ 36.220068] [<ffffffff82c3873b>] sock_diag_rcv+0x1b/0x40
    >>>> #1: [ 36.220068] (
    >>>> sock_diag_table_mutex[ 36.220068] ){+.+.+.}
    >>>> , at: [ 36.220068] [<ffffffff82c38e00>] sock_diag_rcv_msg+0x140/0x3a0
    >>>> #2: [ 36.220068] (
    >>>> nlk->cb_mutex[ 36.220068] ){+.+.+.}
    >>>> , at: [ 36.220068] [<ffffffff82db6600>] netlink_dump+0x50/0xac0
    >>>>
    >>>> stack backtrace:
    >>>> CPU: 1 PID: 4018 Comm: syz-executor Not tainted 4.9.0-rc3+ #336
    >>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    >>>> ffff8800645df688 ffffffff81b46934 ffffffff84eb3e78 ffff88006ad85800
    >>>> ffffffff82dc8683 ffffffff84eb3e78 ffff8800645df6b8 ffffffff812043ca
    >>>> dffffc0000000000 ffff88006ad85ff8 ffff88006ad85fd0 00000000ffffffff
    >>>> Call Trace:
    >>>> [< inline >] __dump_stack lib/dump_stack.c:15
    >>>> [<ffffffff81b46934>] dump_stack+0xb3/0x10f lib/dump_stack.c:51
    >>>> [<ffffffff812043ca>] print_unlock_imbalance_bug+0x17a/0x1a0
    >>>> kernel/locking/lockdep.c:3388
    >>>> [< inline >] __lock_release kernel/locking/lockdep.c:3512
    >>>> [<ffffffff8120cfd8>] lock_release+0x8e8/0xc60 kernel/locking/lockdep.c:3765
    >>>> [< inline >] __raw_read_unlock ./include/linux/rwlock_api_smp.h:225
    >>>> [<ffffffff83fc001a>] _raw_read_unlock+0x1a/0x30 kernel/locking/spinlock.c:255
    >>>> [<ffffffff82dc8683>] netlink_diag_dump+0x1a3/0x250 net/netlink/diag.c:182
    >>>> [<ffffffff82db6947>] netlink_dump+0x397/0xac0 net/netlink/af_netlink.c:2110
    >>>> [<ffffffff82db99b1>] __netlink_dump_start+0x501/0x770
    >>>> net/netlink/af_netlink.c:2200
    >>>> [< inline >] netlink_dump_start ./include/linux/netlink.h:165
    >>>> [<ffffffff82dc75d1>] netlink_diag_handler_dump+0x191/0x220
    >>>> net/netlink/diag.c:218
    >>>> [< inline >] __sock_diag_cmd net/core/sock_diag.c:239
    >>>> [<ffffffff82c38fd6>] sock_diag_rcv_msg+0x316/0x3a0 net/core/sock_diag.c:270
    >>>> [<ffffffff82dc10a0>] netlink_rcv_skb+0x2c0/0x3b0 net/netlink/af_netlink.c:2281
    >>>> [<ffffffff82c3874a>] sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:281
    >>>> [< inline >] netlink_unicast_kernel net/netlink/af_netlink.c:1214
    >>>> [<ffffffff82dbf959>] netlink_unicast+0x5a9/0x880 net/netlink/af_netlink.c:1240
    >>>> [<ffffffff82dc05e7>] netlink_sendmsg+0x9b7/0xce0 net/netlink/af_netlink.c:1786
    >>>> [< inline >] sock_sendmsg_nosec net/socket.c:606
    >>>> [<ffffffff82b6f75c>] sock_sendmsg+0xcc/0x110 net/socket.c:616
    >>>> [<ffffffff82b6f9c1>] sock_write_iter+0x221/0x3b0 net/socket.c:814
    >>>> [< inline >] new_sync_write fs/read_write.c:499
    >>>> [<ffffffff8151bd44>] __vfs_write+0x334/0x570 fs/read_write.c:512
    >>>> [<ffffffff8151f85b>] vfs_write+0x17b/0x500 fs/read_write.c:560
    >>>> [< inline >] SYSC_write fs/read_write.c:607
    >>>> [<ffffffff81523184>] SyS_write+0xd4/0x1a0 fs/read_write.c:599
    >>>> [<ffffffff83fc0401>] entry_SYSCALL_64_fastpath+0x1f/0xc2
    >>>> arch/x86/entry/entry_64.S:209
    >>>> ------------[ cut here ]------------
    >>>> WARNING: CPU: 1 PID: 4018 at net/core/skbuff.c:654[< none
    >>>> >] skb_release_head_state+0x1ca/0x240 net/core/skbuff.c:654
    >>>> Modules linked in:
    >>>> CPU: 1 PID: 4018 Comm: syz-executor Not tainted 4.9.0-rc3+ #336
    >>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    >>>> ffff8800645df920 ffffffff81b46934 0000000000000000 0000000000000000
    >>>> ffffffff84401fa0 0000000000000000 ffff8800645df968 ffffffff811112f7
    >>>> ffffffff83fb92f2 ffff88000000028e ffffffff84401fa0 000000000000028e
    >>>> Call Trace:
    >>>> [< inline >] __dump_stack lib/dump_stack.c:15
    >>>> [<ffffffff81b46934>] dump_stack+0xb3/0x10f lib/dump_stack.c:51
    >>>> [<ffffffff811112f7>] __warn+0x1a7/0x1f0 kernel/panic.c:550
    >>>> [<ffffffff8111150c>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585
    >>>> [<ffffffff82b885ea>] skb_release_head_state+0x1ca/0x240 net/core/skbuff.c:654
    >>>> [<ffffffff82b91815>] skb_release_all+0x15/0x60 net/core/skbuff.c:668
    >>>> [< inline >] __kfree_skb net/core/skbuff.c:684
    >>>> [<ffffffff82ba0175>] consume_skb+0x115/0x2e0 net/core/skbuff.c:757
    >>>> [< inline >] netlink_unicast_kernel net/netlink/af_netlink.c:1215
    >>>> [<ffffffff82dbf961>] netlink_unicast+0x5b1/0x880 net/netlink/af_netlink.c:1240
    >>>> [<ffffffff82dc05e7>] netlink_sendmsg+0x9b7/0xce0 net/netlink/af_netlink.c:1786
    >>>> [< inline >] sock_sendmsg_nosec net/socket.c:606
    >>>> [<ffffffff82b6f75c>] sock_sendmsg+0xcc/0x110 net/socket.c:616
    >>>> [<ffffffff82b6f9c1>] sock_write_iter+0x221/0x3b0 net/socket.c:814
    >>>> [< inline >] new_sync_write fs/read_write.c:499
    >>>> [<ffffffff8151bd44>] __vfs_write+0x334/0x570 fs/read_write.c:512
    >>>> [<ffffffff8151f85b>] vfs_write+0x17b/0x500 fs/read_write.c:560
    >>>> [< inline >] SYSC_write fs/read_write.c:607
    >>>> [<ffffffff81523184>] SyS_write+0xd4/0x1a0 fs/read_write.c:599
    >>>> [<ffffffff83fc0401>] entry_SYSCALL_64_fastpath+0x1f/0xc2
    >>>> arch/x86/entry/entry_64.S:209
    >>>> ---[ end trace bb9fa7cf182d59a5 ]---
    >>>> BUG: scheduling while atomic: syz-executor/4018/0x7fffffff
    >>>> INFO: lockdep is turned off.
    >>>> Modules linked in:
    >>>> CPU: 1 PID: 4018 Comm: syz-executor Tainted: G W 4.9.0-rc3+ #336
    >>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    >>>> ffff8800645dfe28 ffffffff81b46934 dffffc0000000000 000000007fffffff
    >>>> 00000000000214c0 0000000000000001 ffff8800645dfe48 ffffffff8119113a
    >>>> ffff88006cd214c0 0000000000000000 ffff8800645dfec8 ffffffff83fb030a
    >>>> Call Trace:
    >>>> [< inline >] __dump_stack lib/dump_stack.c:15
    >>>> [<ffffffff81b46934>] dump_stack+0xb3/0x10f lib/dump_stack.c:51
    >>>> [<ffffffff8119113a>] __schedule_bug+0xfa/0x140 kernel/sched/core.c:3230
    >>>> [< inline >] schedule_debug kernel/sched/core.c:3245
    >>>> [<ffffffff83fb030a>] __schedule+0xfda/0x1ab0 kernel/sched/core.c:3345
    >>>> [<ffffffff83fb0e70>] schedule+0x90/0x1b0 kernel/sched/core.c:3457
    >>>> [<ffffffff810039e9>] exit_to_usermode_loop+0xc9/0x130
    >>>> arch/x86/entry/common.c:149
    >>>> [< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:190
    >>>> [<ffffffff81006298>] syscall_return_slowpath+0x1a8/0x1e0
    >>>> arch/x86/entry/common.c:259
    >>>> [<ffffffff83fc04a2>] entry_SYSCALL_64_fastpath+0xc0/0xc2
    >>>> arch/x86/entry/entry_64.S:244
    >>>> NOHZ: local_softirq_pending 202
    >>>> ------------[ cut here ]------------
    >>>> WARNING: CPU: 1 PID: 4018 at net/core/skbuff.c:654[< none
    >>>> >] skb_release_head_state+0x1ca/0x240 net/core/skbuff.c:654
    >>>> Modules linked in:[ 36.328353] CPU: 1 PID: 4018 Comm: syz-executor
    >>>> Tainted: G W 4.9.0-rc3+ #336
    >>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    >>>> ffff8800645df920 ffffffff81b46934 0000000000000000 0000000000000000
    >>>> ffffffff84401fa0 0000000000000000 ffff8800645df968 ffffffff811112f7
    >>>> ffffffff83fb92f2 ffff88000000028e ffffffff84401fa0 000000000000028e
    >>>> Call Trace:
    >>>> [< inline >] __dump_stack lib/dump_stack.c:15
    >>>> [<ffffffff81b46934>] dump_stack+0xb3/0x10f lib/dump_stack.c:51
    >>>> [<ffffffff811112f7>] __warn+0x1a7/0x1f0 kernel/panic.c:550
    >>>> [<ffffffff8111150c>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585
    >>>> [<ffffffff82b885ea>] skb_release_head_state+0x1ca/0x240 net/core/skbuff.c:654
    >>>> [<ffffffff82b91815>] skb_release_all+0x15/0x60 net/core/skbuff.c:668
    >>>> [< inline >] __kfree_skb net/core/skbuff.c:684
    >>>> [<ffffffff82ba0175>] consume_skb+0x115/0x2e0 net/core/skbuff.c:757
    >>>> [< inline >] netlink_unicast_kernel net/netlink/af_netlink.c:1215
    >>>> [<ffffffff82dbf961>] netlink_unicast+0x5b1/0x880 net/netlink/af_netlink.c:1240
    >>>> [<ffffffff82dc05e7>] netlink_sendmsg+0x9b7/0xce0 net/netlink/af_netlink.c:1786
    >>>> [< inline >] sock_sendmsg_nosec net/socket.c:606
    >>>> [<ffffffff82b6f75c>] sock_sendmsg+0xcc/0x110 net/socket.c:616
    >>>> [<ffffffff82b6f9c1>] sock_write_iter+0x221/0x3b0 net/socket.c:814
    >>>> [< inline >] new_sync_write fs/read_write.c:499
    >>>> [<ffffffff8151bd44>] __vfs_write+0x334/0x570 fs/read_write.c:512
    >>>> [<ffffffff8151f85b>] vfs_write+0x17b/0x500 fs/read_write.c:560
    >>>> [< inline >] SYSC_write fs/read_write.c:607
    >>>> [<ffffffff81523184>] SyS_write+0xd4/0x1a0 fs/read_write.c:599
    >>>> [<ffffffff83fc0401>] entry_SYSCALL_64_fastpath+0x1f/0xc2
    >>>> arch/x86/entry/entry_64.S:209
    >>>> ---[ end trace bb9fa7cf182d59a6 ]---
    >>>> BUG: sleeping function called from invalid context at
    >>>> ./include/linux/freezer.h:56
    >>>> in_atomic(): 1, irqs_disabled(): 0, pid: 4018, name: syz-executor
    >>>> INFO: lockdep is turned off.
    >>>> CPU: 1 PID: 4018 Comm: syz-executor Tainted: G W 4.9.0-rc3+ #336
    >>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    >>>> ffff8800645dfbb0 ffffffff81b46934 ffff88006ad85800 ffff8800645d8000
    >>>> ffff88006ad85800 0000000000000000 ffff8800645dfbd8 ffffffff81192131
    >>>> ffff88006ad85800 ffffffff8404c140 0000000000000038 ffff8800645dfc18
    >>>> Call Trace:
    >>>> [< inline >] __dump_stack lib/dump_stack.c:15
    >>>> [<ffffffff81b46934>] dump_stack+0xb3/0x10f lib/dump_stack.c:51
    >>>> [<ffffffff81192131>] ___might_sleep+0x281/0x3c0 kernel/sched/core.c:7767
    >>>> [<ffffffff81192306>] __might_sleep+0x96/0x1a0 kernel/sched/core.c:7726
    >>>> [< inline >] try_to_freeze_unsafe ./include/linux/freezer.h:56
    >>>> [< inline >] try_to_freeze ./include/linux/freezer.h:66
    >>>> [<ffffffff81143849>] get_signal+0x129/0x15a0 kernel/signal.c:2147
    >>>> [<ffffffff81054aad>] do_signal+0x8d/0x1a30 arch/x86/kernel/signal.c:807
    >>>> [<ffffffff81003a05>] exit_to_usermode_loop+0xe5/0x130
    >>>> arch/x86/entry/common.c:156
    >>>> [< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:190
    >>>> [<ffffffff81006298>] syscall_return_slowpath+0x1a8/0x1e0
    >>>> arch/x86/entry/common.c:259
    >>>> [<ffffffff83fc04a2>] entry_SYSCALL_64_fastpath+0xc0/0xc2
    >>>> arch/x86/entry/entry_64.S:244
    >>>> Kernel panic - not syncing: Aiee, killing interrupt handler!
    >>>> CPU: 1 PID: 4018 Comm: syz-executor Tainted: G W 4.9.0-rc3+ #336
    >>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    >>>> ffff8800645df998 ffffffff81b46934 0000000000000003 dffffc0000000000
    >>>> dffffc0000000000 ffff8800645dfa04 ffff8800645dfa60 ffffffff8140bf7a
    >>>> 0000000041b58ab3 ffffffff84797a7d ffffffff8140bdbe ffffffff00000000
    >>>> Call Trace:
    >>>> [< inline >] __dump_stack lib/dump_stack.c:15
    >>>> [<ffffffff81b46934>] dump_stack+0xb3/0x10f lib/dump_stack.c:51
    >>>> [<ffffffff8140bf7a>] panic+0x1bc/0x39d kernel/panic.c:179
    >>>> [<ffffffff8111cfd8>] do_exit+0x1b48/0x2ac0 kernel/exit.c:740
    >>>> [<ffffffff811222be>] do_group_exit+0x10e/0x340 kernel/exit.c:931
    >>>> [<ffffffff81143d54>] get_signal+0x634/0x15a0 kernel/signal.c:2307
    >>>> [<ffffffff81054aad>] do_signal+0x8d/0x1a30 arch/x86/kernel/signal.c:807
    >>>> [<ffffffff81003a05>] exit_to_usermode_loop+0xe5/0x130
    >>>> arch/x86/entry/common.c:156
    >>>> [< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:190
    >>>> [<ffffffff81006298>] syscall_return_slowpath+0x1a8/0x1e0
    >>>> arch/x86/entry/common.c:259
    >>>> [<ffffffff83fc04a2>] entry_SYSCALL_64_fastpath+0xc0/0xc2
    >>>> arch/x86/entry/entry_64.S:244
    >>>> Kernel Offset: disabled
    >>>> ---[ end Kernel panic - not syncing: Aiee, killing interrupt handler!
    >>>
    >>>
    >>> This is probably a leftover after commit
    >>> ad202074320cd75b31b8cdb58cca0d4ef6aaea8a
    >>> ("netlink: Use rhashtable walk interface in diag dump")
    >>>
    >>> Please try this trivial fix :
    >>>
    >>> diff --git a/net/netlink/diag.c b/net/netlink/diag.c
    >>> index b2f0e986a6f4..a5546249fb10 100644
    >>> --- a/net/netlink/diag.c
    >>> +++ b/net/netlink/diag.c
    >>> @@ -178,11 +178,8 @@ static int netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
    >>> }
    >>> cb->args[1] = i;
    >>> } else {
    >>> - if (req->sdiag_protocol >= MAX_LINKS) {
    >>> - read_unlock(&nl_table_lock);
    >>> - rcu_read_unlock();
    >>> + if (req->sdiag_protocol >= MAX_LINKS)
    >>> return -ENOENT;
    >>> - }
    >>>
    >>> err = __netlink_diag_dump(skb, cb, req->sdiag_protocol, s_num);
    >>> }
    >>>
    >>>




    ping

    I am seeing thousands of these deadlock reports on commit
    623898671c8eb05639e746e6d84cffa281616438:


    [ INFO: possible circular locking dependency detected ]
    4.9.0-rc5+ #54 Not tainted
    -------------------------------------------------------
    syz-executor/12883 is trying to acquire lock:
    ([ 450.846039] rtnl_mutex
    [<ffffffff86b3d34c>] rtnl_lock+0x1c/0x20 net/core/rtnetlink.c:70

    but task is already holding lock:
    ([ 450.846039] genl_mutex
    [< inline >] genl_lock net/netlink/genetlink.c:31
    [<ffffffff86cb5ab6>] genl_lock_dumpit+0x46/0xa0 net/netlink/genetlink.c:518

    which lock already depends on the new lock.


    the existing dependency chain (in reverse order) is:

    :
    [ 450.853245] [< inline >] validate_chain
    kernel/locking/lockdep.c:2266
    [ 450.853245] [<ffffffff81569546>]
    __lock_acquire+0x2156/0x3380 kernel/locking/lockdep.c:3335
    [ 450.853245] [<ffffffff8156b642>] lock_acquire+0x2a2/0x790
    kernel/locking/lockdep.c:3746
    [ 450.853245] [< inline >] __mutex_lock_common
    kernel/locking/mutex.c:521
    [ 450.853245] [<ffffffff88139aff>]
    mutex_lock_nested+0x23f/0xf20 kernel/locking/mutex.c:621
    [ 450.862462] [< inline >] genl_lock net/netlink/genetlink.c:31
    [ 450.862462] [<ffffffff86cb5ab6>] genl_lock_dumpit+0x46/0xa0
    net/netlink/genetlink.c:518
    [ 450.862462] [<ffffffff86ca8256>] netlink_dump+0x576/0xd70
    net/netlink/af_netlink.c:2110
    [ 450.862462] [<ffffffff86caca1a>]
    __netlink_dump_start+0x4ea/0x760 net/netlink/af_netlink.c:2200
    [ 450.862462] [<ffffffff86cb7199>]
    genl_family_rcv_msg+0xdc9/0x1070 net/netlink/genetlink.c:586
    [ 450.866287] [<ffffffff86cb75f0>] genl_rcv_msg+0x1b0/0x260
    net/netlink/genetlink.c:660
    [ 450.867554] [<ffffffff86cb51e0>] netlink_rcv_skb+0x2b0/0x390
    net/netlink/af_netlink.c:2281
    [ 450.870045] [<ffffffff86cb63bd>] genl_rcv+0x2d/0x40
    net/netlink/genetlink.c:671
    [ 450.870045] [< inline >] netlink_unicast_kernel
    net/netlink/af_netlink.c:1214
    [ 450.870045] [<ffffffff86cb3a14>] netlink_unicast+0x514/0x730
    net/netlink/af_netlink.c:1240
    [ 450.870045] [<ffffffff86cb46d4>] netlink_sendmsg+0xaa4/0xe50
    net/netlink/af_netlink.c:1786
    [ 450.870045] [< inline >] sock_sendmsg_nosec net/socket.c:621
    [ 450.870045] [<ffffffff86a6d54f>] sock_sendmsg+0xcf/0x110
    net/socket.c:631
    [ 450.870045] [<ffffffff86a6d8bb>] sock_write_iter+0x32b/0x620
    net/socket.c:829
    [ 450.870045] [< inline >] new_sync_write fs/read_write.c:499
    [ 450.870045] [<ffffffff81a6f24e>] __vfs_write+0x4fe/0x830
    fs/read_write.c:512
    [ 450.870045] [<ffffffff81a70cf5>] vfs_write+0x175/0x4e0
    fs/read_write.c:560
    [ 450.870045] [< inline >] SYSC_write fs/read_write.c:607
    [ 450.870045] [<ffffffff81a75180>] SyS_write+0x100/0x240
    fs/read_write.c:599
    [ 450.870045] [<ffffffff88149dc5>] entry_SYSCALL_64_fastpath+0x23/0xc6

    :
    [ 450.870045] [< inline >] validate_chain
    kernel/locking/lockdep.c:2266
    [ 450.870045] [<ffffffff81569546>]
    __lock_acquire+0x2156/0x3380 kernel/locking/lockdep.c:3335
    [ 450.870045] [<ffffffff8156b642>] lock_acquire+0x2a2/0x790
    kernel/locking/lockdep.c:3746
    [ 450.870045] [< inline >] __mutex_lock_common
    kernel/locking/mutex.c:521
    [ 450.870045] [<ffffffff88139aff>]
    mutex_lock_nested+0x23f/0xf20 kernel/locking/mutex.c:621
    [ 450.870045] [<ffffffff86cac629>]
    __netlink_dump_start+0xf9/0x760 net/netlink/af_netlink.c:2170
    [ 450.870045] [< inline >] netlink_dump_start
    include/linux/netlink.h:165
    [ 450.870045] [<ffffffff86d09dfc>]
    ctnetlink_get_conntrack+0x71c/0xa90
    net/netfilter/nf_conntrack_netlink.c:1205
    [ 450.870045] [<ffffffff86cc7c3e>]
    nfnetlink_rcv_msg+0x9be/0xd60 net/netfilter/nfnetlink.c:212
    [ 450.886719] [<ffffffff86cb51e0>] netlink_rcv_skb+0x2b0/0x390
    net/netlink/af_netlink.c:2281
    [ 450.886719] [<ffffffff86cc666c>] nfnetlink_rcv+0x7cc/0x10c0
    net/netfilter/nfnetlink.c:474
    [ 450.889046] [< inline >] netlink_unicast_kernel
    net/netlink/af_netlink.c:1214
    [ 450.889046] [<ffffffff86cb3a14>] netlink_unicast+0x514/0x730
    net/netlink/af_netlink.c:1240
    [ 450.889046] [<ffffffff86cb46d4>] netlink_sendmsg+0xaa4/0xe50
    net/netlink/af_netlink.c:1786
    [ 450.889046] [< inline >] sock_sendmsg_nosec net/socket.c:621
    [ 450.889046] [<ffffffff86a6d54f>] sock_sendmsg+0xcf/0x110
    net/socket.c:631
    [ 450.889046] [<ffffffff86a6d8bb>] sock_write_iter+0x32b/0x620
    net/socket.c:829
    [ 450.889046] [< inline >] new_sync_write fs/read_write.c:499
    [ 450.889046] [<ffffffff81a6f24e>] __vfs_write+0x4fe/0x830
    fs/read_write.c:512
    [ 450.894033] [<ffffffff81a70cf5>] vfs_write+0x175/0x4e0
    fs/read_write.c:560
    [ 450.894033] [< inline >] SYSC_write fs/read_write.c:607
    [ 450.894033] [<ffffffff81a75180>] SyS_write+0x100/0x240
    fs/read_write.c:599
    [ 450.894033] [<ffffffff81009a24>] do_syscall_64+0x2f4/0x940
    arch/x86/entry/common.c:280
    [ 450.894033] [<ffffffff88149e8d>] return_from_SYSCALL_64+0x0/0x7a

    :
    [ 450.900551] [< inline >] validate_chain
    kernel/locking/lockdep.c:2266
    [ 450.900551] [<ffffffff81569546>]
    __lock_acquire+0x2156/0x3380 kernel/locking/lockdep.c:3335
    [ 450.900551] [<ffffffff8156b642>] lock_acquire+0x2a2/0x790
    kernel/locking/lockdep.c:3746
    [ 450.900551] [< inline >] __mutex_lock_common
    kernel/locking/mutex.c:521
    [ 450.900551] [<ffffffff88139aff>]
    mutex_lock_nested+0x23f/0xf20 kernel/locking/mutex.c:621
    [ 450.900551] [<ffffffff86cc534d>] nfnl_lock+0x2d/0x30
    net/netfilter/nfnetlink.c:61
    [ 450.900551] [<ffffffff86d62e51>]
    nf_tables_netdev_event+0x1f1/0x720
    net/netfilter/nf_tables_netdev.c:122
    [ 450.900551] [<ffffffff814908ea>]
    notifier_call_chain+0x14a/0x2f0 kernel/notifier.c:93
    [ 450.900551] [< inline >] __raw_notifier_call_chain
    kernel/notifier.c:394
    [ 450.900551] [<ffffffff81490b12>]
    raw_notifier_call_chain+0x32/0x40 kernel/notifier.c:401
    [ 450.900551] [<ffffffff86adb746>]
    call_netdevice_notifiers_info+0x56/0x90 net/core/dev.c:1645
    [ 450.900551] [< inline >] call_netdevice_notifiers
    net/core/dev.c:1661
    [ 450.900551] [<ffffffff86aef59d>]
    rollback_registered_many+0x73d/0xba0 net/core/dev.c:6759
    [ 450.900551] [<ffffffff86aefaae>]
    rollback_registered+0xae/0x100 net/core/dev.c:6800
    [ 450.900551] [<ffffffff86aefb86>]
    unregister_netdevice_queue+0x86/0x140 net/core/dev.c:7787
    [ 450.900551] [< inline >] unregister_netdevice
    include/linux/netdevice.h:2455
    [ 450.900551] [<ffffffff8490cc36>] __tun_detach+0xc66/0xea0
    drivers/net/tun.c:567
    [ 450.900551] [< inline >] tun_detach drivers/net/tun.c:578
    [ 450.900551] [<ffffffff8490ceb9>] tun_chr_close+0x49/0x60
    drivers/net/tun.c:2352
    [ 450.900551] [<ffffffff81a7701e>] __fput+0x34e/0x910
    fs/file_table.c:208
    [ 450.900551] [<ffffffff81a7766a>] ____fput+0x1a/0x20
    fs/file_table.c:244
    [ 450.900551] [<ffffffff81483bb0>] task_work_run+0x1a0/0x280
    kernel/task_work.c:116
    [ 450.900551] [< inline >] exit_task_work
    include/linux/task_work.h:21
    [ 450.900551] [<ffffffff8141297a>] do_exit+0x183a/0x2640
    kernel/exit.c:828
    [ 450.900551] [<ffffffff8141393e>] do_group_exit+0x14e/0x420
    kernel/exit.c:931
    [ 450.900551] [<ffffffff81442ad3>] get_signal+0x663/0x1880
    kernel/signal.c:2307
    [ 450.900551] [<ffffffff81239b45>] do_signal+0xc5/0x2190
    arch/x86/kernel/signal.c:807
    [ 450.900551] [<ffffffff8100666a>]
    exit_to_usermode_loop+0x1ea/0x2d0 arch/x86/entry/common.c:156
    [ 450.900551] [< inline >] prepare_exit_to_usermode
    arch/x86/entry/common.c:190
    [ 450.900551] [<ffffffff81009693>]
    syscall_return_slowpath+0x4d3/0x570 arch/x86/entry/common.c:259
    [ 450.900551] [<ffffffff88149e66>] entry_SYSCALL_64_fastpath+0xc4/0xc6

    :
    [ 450.900551] [< inline >] check_prev_add
    kernel/locking/lockdep.c:1829
    [ 450.900551] [<ffffffff8156306b>]
    check_prevs_add+0xaab/0x1c20 kernel/locking/lockdep.c:1939
    [ 450.900551] [< inline >] validate_chain
    kernel/locking/lockdep.c:2266
    [ 450.900551] [<ffffffff81569546>]
    __lock_acquire+0x2156/0x3380 kernel/locking/lockdep.c:3335
    [ 450.900551] [<ffffffff8156b642>] lock_acquire+0x2a2/0x790
    kernel/locking/lockdep.c:3746
    [ 450.900551] [< inline >] __mutex_lock_common
    kernel/locking/mutex.c:521
    [ 450.900551] [<ffffffff88139aff>]
    mutex_lock_nested+0x23f/0xf20 kernel/locking/mutex.c:621
    [ 450.900551] [<ffffffff86b3d34c>] rtnl_lock+0x1c/0x20
    net/core/rtnetlink.c:70
    [ 450.900551] [<ffffffff87efd7c7>]
    ieee802154_nl_fill_phy.isra.6+0x127/0x690 net/ieee802154/nl-phy.c:53
    [ 450.900551] [<ffffffff87efde82>]
    ieee802154_dump_phy_iter+0x152/0x200 net/ieee802154/nl-phy.c:137
    [ 450.900551] [<ffffffff87eff49f>] wpan_phy_iter+0x5f/0x80
    net/ieee802154/core.c:65
    [ 450.900551] [<ffffffff8416f508>]
    class_for_each_device+0x138/0x240 drivers/base/class.c:382
    [ 450.900551] [<ffffffff87eff690>]
    wpan_phy_for_each+0xc0/0x110 net/ieee802154/core.c:76
    [ 450.900551] [<ffffffff87efe383>]
    ieee802154_dump_phy+0x153/0x2a0 net/ieee802154/nl-phy.c:162
    [ 450.900551] [<ffffffff86cb5add>] genl_lock_dumpit+0x6d/0xa0
    net/netlink/genetlink.c:519
    [ 450.900551] [<ffffffff86ca8256>] netlink_dump+0x576/0xd70
    net/netlink/af_netlink.c:2110
    [ 450.900551] [<ffffffff86caca1a>]
    __netlink_dump_start+0x4ea/0x760 net/netlink/af_netlink.c:2200
    [ 450.900551] [<ffffffff86cb7199>]
    genl_family_rcv_msg+0xdc9/0x1070 net/netlink/genetlink.c:586
    [ 450.900551] [<ffffffff86cb75f0>] genl_rcv_msg+0x1b0/0x260
    net/netlink/genetlink.c:660
    [ 450.900551] [<ffffffff86cb51e0>] netlink_rcv_skb+0x2b0/0x390
    net/netlink/af_netlink.c:2281
    [ 450.900551] [<ffffffff86cb63bd>] genl_rcv+0x2d/0x40
    net/netlink/genetlink.c:671
    [ 450.900551] [< inline >] netlink_unicast_kernel
    net/netlink/af_netlink.c:1214
    [ 450.900551] [<ffffffff86cb3a14>] netlink_unicast+0x514/0x730
    net/netlink/af_netlink.c:1240
    [ 450.900551] [<ffffffff86cb46d4>] netlink_sendmsg+0xaa4/0xe50
    net/netlink/af_netlink.c:1786
    [ 450.900551] [< inline >] sock_sendmsg_nosec net/socket.c:621
    [ 450.900551] [<ffffffff86a6d54f>] sock_sendmsg+0xcf/0x110
    net/socket.c:631
    [ 450.900551] [<ffffffff86a6d8bb>] sock_write_iter+0x32b/0x620
    net/socket.c:829
    [ 450.900551] [< inline >] new_sync_write fs/read_write.c:499
    [ 450.900551] [<ffffffff81a6f24e>] __vfs_write+0x4fe/0x830
    fs/read_write.c:512
    [ 450.900551] [<ffffffff81a70cf5>] vfs_write+0x175/0x4e0
    fs/read_write.c:560
    [ 450.900551] [< inline >] SYSC_write fs/read_write.c:607
    [ 450.900551] [<ffffffff81a75180>] SyS_write+0x100/0x240
    fs/read_write.c:599
    [ 450.900551] [<ffffffff88149dc5>] entry_SYSCALL_64_fastpath+0x23/0xc6

    other info that might help us debug this:

    Chain exists of:


    Possible unsafe locking scenario:

    CPU0 CPU1
    ---- ----
    lock([ 450.958731] genl_mutex
    );
    lock([ 450.958731] nlk->cb_mutex
    QAT: Invalid ioctl
    );
    lock([ 450.958731] genl_mutex
    );
    lock([ 450.958731] rtnl_mutex
    );

    *** DEADLOCK ***

    QAT: Invalid ioctl
    3 locks held by syz-executor/12883:
    #0: [ 450.958731] (
    #1: [ 450.958731] (
    #2: [ 450.958731] (

    stack backtrace:
    CPU: 2 PID: 12883 Comm: syz-executor Not tainted 4.9.0-rc5+ #54
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    ffff880069616088 ffffffff834c2e39 ffffffff00000002 1ffff1000d2c2ba4
    ffffed000d2c2b9c 0000000041b58ab3 ffffffff89575550 ffffffff834c2b4b
    0000000000000000 0000000000000000 0000000000000000 0000000000000000
    Call Trace:
    [< inline >] __dump_stack lib/dump_stack.c:15
    [<ffffffff834c2e39>] dump_stack+0x2ee/0x3f5 lib/dump_stack.c:51
    [<ffffffff81560c70>] print_circular_bug+0x310/0x3c0
    kernel/locking/lockdep.c:1202
    [< inline >] check_prev_add kernel/locking/lockdep.c:1829
    [<ffffffff8156306b>] check_prevs_add+0xaab/0x1c20 kernel/locking/lockdep.c:1939
    [< inline >] validate_chain kernel/locking/lockdep.c:2266
    [<ffffffff81569546>] __lock_acquire+0x2156/0x3380 kernel/locking/lockdep.c:3335
    [<ffffffff8156b642>] lock_acquire+0x2a2/0x790 kernel/locking/lockdep.c:3746
    [< inline >] __mutex_lock_common kernel/locking/mutex.c:521
    [<ffffffff88139aff>] mutex_lock_nested+0x23f/0xf20 kernel/locking/mutex.c:621
    [<ffffffff86b3d34c>] rtnl_lock+0x1c/0x20 net/core/rtnetlink.c:70
    [<ffffffff87efd7c7>] ieee802154_nl_fill_phy.isra.6+0x127/0x690
    net/ieee802154/nl-phy.c:53
    [<ffffffff87efde82>] ieee802154_dump_phy_iter+0x152/0x200
    net/ieee802154/nl-phy.c:137
    [<ffffffff87eff49f>] wpan_phy_iter+0x5f/0x80 net/ieee802154/core.c:65
    [<ffffffff8416f508>] class_for_each_device+0x138/0x240 drivers/base/class.c:382
    [<ffffffff87eff690>] wpan_phy_for_each+0xc0/0x110 net/ieee802154/core.c:76
    [<ffffffff87efe383>] ieee802154_dump_phy+0x153/0x2a0
    net/ieee802154/nl-phy.c:162
    [<ffffffff86cb5add>] genl_lock_dumpit+0x6d/0xa0 net/netlink/genetlink.c:519
    [<ffffffff86ca8256>] netlink_dump+0x576/0xd70 net/netlink/af_netlink.c:2110
    [<ffffffff86caca1a>] __netlink_dump_start+0x4ea/0x760
    net/netlink/af_netlink.c:2200
    [<ffffffff86cb7199>] genl_family_rcv_msg+0xdc9/0x1070
    net/netlink/genetlink.c:586
    [<ffffffff86cb75f0>] genl_rcv_msg+0x1b0/0x260 net/netlink/genetlink.c:660
    [<ffffffff86cb51e0>] netlink_rcv_skb+0x2b0/0x390 net/netlink/af_netlink.c:2281
    [<ffffffff86cb63bd>] genl_rcv+0x2d/0x40 net/netlink/genetlink.c:671
    [< inline >] netlink_unicast_kernel net/netlink/af_netlink.c:1214
    [<ffffffff86cb3a14>] netlink_unicast+0x514/0x730 net/netlink/af_netlink.c:1240
    [<ffffffff86cb46d4>] netlink_sendmsg+0xaa4/0xe50 net/netlink/af_netlink.c:1786
    [< inline >] sock_sendmsg_nosec net/socket.c:621
    [<ffffffff86a6d54f>] sock_sendmsg+0xcf/0x110 net/socket.c:631
    [<ffffffff86a6d8bb>] sock_write_iter+0x32b/0x620 net/socket.c:829
    [< inline >] new_sync_write fs/read_write.c:499
    [<ffffffff81a6f24e>] __vfs_write+0x4fe/0x830 fs/read_write.c:512
    [<ffffffff81a70cf5>] vfs_write+0x175/0x4e0 fs/read_write.c:560
    [< inline >] SYSC_write fs/read_write.c:607
    [<ffffffff81a75180>] SyS_write+0x100/0x240 fs/read_write.c:599
    [<ffffffff88149dc5>] entry_SYSCALL_64_fastpath+0x23/0xc6

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