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Subject: Re: INFO: task hung in tcf_ife_init
To:     syzbot <syzbot+80e32b5d1f9923f8ace6@syzkaller.appspotmail.com>,
        davem@davemloft.net, jhs@mojatatu.com, jiri@resnulli.us,
        kuba@kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com,
        xiyou.wangcong@gmail.com
References: <00000000000014fd1405ae64d01f@google.com>
From:   Eric Dumazet <eric.dumazet@gmail.com>
Message-ID: <af0a0922-86cb-fcab-0aeb-a842c5c34707@gmail.com>
Date:   Thu, 3 Sep 2020 11:47:05 +0200
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On 9/3/20 1:48 AM, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    1996cf46 net: bcmgenet: fix mask check in bcmgenet_validat..
> git tree:       net
> console output: https://syzkaller.appspot.com/x/log.txt?x=17233f4d900000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=a0437fdd630bee11
> dashboard link: https://syzkaller.appspot.com/bug?extid=80e32b5d1f9923f8ace6
> compiler:       gcc (GCC) 10.1.0-syz 20200507
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=161678e1900000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14f826d1900000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+80e32b5d1f9923f8ace6@syzkaller.appspotmail.com
> 
> INFO: task syz-executor939:6846 blocked for more than 143 seconds.
>       Not tainted 5.9.0-rc1-syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:syz-executor939 state:D stack:25032 pid: 6846 ppid:  6839 flags:0x00004004
> Call Trace:
>  context_switch kernel/sched/core.c:3778 [inline]
>  __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527
>  schedule+0xd0/0x2a0 kernel/sched/core.c:4602
>  schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
>  __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
>  __mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
>  load_metaops_and_vet net/sched/act_ife.c:277 [inline]
>  populate_metalist net/sched/act_ife.c:452 [inline]
>  tcf_ife_init+0x11a4/0x16f0 net/sched/act_ife.c:578
>  tcf_action_init_1+0x6a5/0xac0 net/sched/act_api.c:984
>  tcf_action_init+0x249/0x380 net/sched/act_api.c:1043
>  tcf_action_add+0xd9/0x360 net/sched/act_api.c:1451
>  tc_ctl_action+0x33a/0x439 net/sched/act_api.c:1504
>  rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
>  netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
>  netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
>  netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
>  netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
>  sock_sendmsg_nosec net/socket.c:651 [inline]
>  sock_sendmsg+0xcf/0x120 net/socket.c:671
>  ____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
>  ___sys_sendmsg+0xf3/0x170 net/socket.c:2407
>  __sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
>  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x445e29
> Code: Bad RIP value.
> RSP: 002b:00007f9e83d9ddb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00000000006dac28 RCX: 0000000000445e29
> RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000003
> RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000006 R11: 0000000000000246 R12: 00000000006dac2c
> R13: 00007fff2893048f R14: 00007f9e83d9e9c0 R15: 20c49ba5e353f7cf
> 
> Showing all locks held in the system:
> 3 locks held by kworker/0:2/48:
>  #0: ffff888214d82538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>  #0: ffff888214d82538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
>  #0: ffff888214d82538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
>  #0: ffff888214d82538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
>  #0: ffff888214d82538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
>  #0: ffff888214d82538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
>  #1: ffffc90000e47da8 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
>  #2: ffffffff8a7e76c8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4568
> 1 lock held by khungtaskd/1166:
>  #0: ffffffff89bd6900 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5825
> 1 lock held by in:imklog/6548:
>  #0: ffff8880a8d05870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930
> 1 lock held by syz-executor939/6846:
>  #0: ffffffff8a7e76c8 (rtnl_mutex){+.+.}-{3:3}, at: load_metaops_and_vet net/sched/act_ife.c:277 [inline]
>  #0: ffffffff8a7e76c8 (rtnl_mutex){+.+.}-{3:3}, at: populate_metalist net/sched/act_ife.c:452 [inline]
>  #0: ffffffff8a7e76c8 (rtnl_mutex){+.+.}-{3:3}, at: tcf_ife_init+0x11a4/0x16f0 net/sched/act_ife.c:578
> 1 lock held by syz-executor939/6848:
> 
> =============================================
> 
> NMI backtrace for cpu 0
> CPU: 0 PID: 1166 Comm: khungtaskd Not tainted 5.9.0-rc1-syzkaller #0
> 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+0x18f/0x20d lib/dump_stack.c:118
>  nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
>  nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
>  trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
>  check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
>  watchdog+0xd7d/0x1000 kernel/hung_task.c:295
>  kthread+0x3b5/0x4a0 kernel/kthread.c:292
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
> Sending NMI from CPU 0 to CPUs 1:
> NMI backtrace for cpu 1
> CPU: 1 PID: 6848 Comm: syz-executor939 Not tainted 5.9.0-rc1-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:arch_local_irq_restore+0x2e/0x50 arch/x86/include/asm/paravirt.h:770
> Code: 3b b6 89 53 48 89 fb 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 18 48 83 3d 41 e6 5c 08 00 74 0c 48 89 df 57 9d <0f> 1f 44 00 00 5b c3 0f 0b 48 c7 c7 c8 3b b6 89 e8 bd 01 5b 00 eb
> RSP: 0018:ffffc9000527ec78 EFLAGS: 00000286
> RAX: 1ffffffff136c779 RBX: 0000000000000286 RCX: 0000000000000000
> RDX: dffffc0000000000 RSI: ffffffff89bd6840 RDI: 0000000000000286
> RBP: ffff888093c08440 R08: ffffffff865a9e38 R09: ffff888099edb807
> R10: ffffed10133db700 R11: 0000000000000001 R12: 0000000000000000
> R13: ffff888093c08d28 R14: ffff888093c08d28 R15: 0000000000000286
> FS:  00007f9e83d7d700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f6aa9c91000 CR3: 0000000091d8f000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  lock_is_held_type+0xbb/0xf0 kernel/locking/lockdep.c:5044
>  lock_is_held include/linux/lockdep.h:267 [inline]
>  ___might_sleep+0x268/0x2f0 kernel/sched/core.c:7265
>  __mutex_lock_common kernel/locking/mutex.c:935 [inline]
>  __mutex_lock+0xa9/0x10e0 kernel/locking/mutex.c:1103
>  tcf_idr_check_alloc+0x78/0x3b0 net/sched/act_api.c:508
>  tcf_ife_init+0x3b1/0x16f0 net/sched/act_ife.c:513
>  tcf_action_init_1+0x6a5/0xac0 net/sched/act_api.c:984
>  tcf_action_init+0x249/0x380 net/sched/act_api.c:1043
>  tcf_action_add+0xd9/0x360 net/sched/act_api.c:1451
>  tc_ctl_action+0x33a/0x439 net/sched/act_api.c:1504
>  rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
>  netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
>  netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
>  netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
>  netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
>  sock_sendmsg_nosec net/socket.c:651 [inline]
>  sock_sendmsg+0xcf/0x120 net/socket.c:671
>  ____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
>  ___sys_sendmsg+0xf3/0x170 net/socket.c:2407
>  __sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
>  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x445e29
> Code: e8 bc b7 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 ab 11 fc ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007f9e83d7cdb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00000000006dac38 RCX: 0000000000445e29
> RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000004
> RBP: 00000000006dac30 R08: 0000000000000003 R09: 0000000000000000
> R10: 0000000000000003 R11: 0000000000000246 R12: 00000000006dac3c
> R13: 00007fff2893048f R14: 00007f9e83d7d9c0 R15: 20c49ba5e353f7cf
> INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 0.000 msecs
> 
> 
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
> 
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches
> 

This commit might be related :

commit 4e407ff5cd67ec76eeeea1deec227b7982dc7f66
Author: Cong Wang <xiyou.wangcong@gmail.com>
Date:   Sun Aug 19 12:22:12 2018 -0700

    act_ife: move tcfa_lock down to where necessary
   
    The only time we need to take tcfa_lock is when adding
    a new metainfo to an existing ife->metalist. We don't need
    to take tcfa_lock so early and so broadly in tcf_ife_init().
   
    This means we can always take ife_mod_lock first, avoid the
    reverse locking ordering warning as reported by Vlad.
   
    Reported-by: Vlad Buslov <vladbu@mellanox.com>
    Tested-by: Vlad Buslov <vladbu@mellanox.com>
    Cc: Vlad Buslov <vladbu@mellanox.com>
    Cc: Jamal Hadi Salim <jhs@mojatatu.com>
    Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>