Re: possible deadlock in rtnl_lock (2)
syzbot wrote: #syz-fix: netfilter: on sockopt() acquire sock lock only in the required scope
Re: possible deadlock in rtnl_lock (2)
On Sat, Feb 3, 2018 at 12:25 PM, Xin Long wrote:
> On Thu, Feb 1, 2018 at 7:58 PM, syzbot
> wrote:
>> Hello,
>>
>> syzbot hit the following crash on upstream commit
>> 255442c93843f52b6891b21d0b485bf2c97f93c3 (Thu Feb 1 03:25:25 2018 +)
>> Merge tag 'docs-4.16' of git://git.lwn.net/linux
>>
>> So far this crash happened 1587 times on net-next, upstream.
>> C reproducer is attached.
>> syzkaller reproducer is attached.
>> Raw console output is attached.
>> compiler: gcc (GCC) 7.1.1 20170620
>> .config is attached.
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+61e4972c2b1d5e08a...@syzkaller.appspotmail.com
>> It will help syzbot understand when the bug is fixed. See footer for
>> details.
>> If you forward the report, please keep this part and the footer.
>>
>>
>> ==
>> WARNING: possible circular locking dependency detected
>> 4.15.0+ #290 Not tainted
>> --
>> syzkaller681093/4124 is trying to acquire lock:
>> (rtnl_mutex){+.+.}, at: [] rtnl_lock+0x17/0x20
>> net/core/rtnetlink.c:74
>>
>> but task is already holding lock:
>> (sk_lock-AF_INET){+.+.}, at: [<51813e83>] lock_sock
>> include/net/sock.h:1461 [inline]
>> (sk_lock-AF_INET){+.+.}, at: [<51813e83>] ip_setsockopt+0x8c/0xb0
>> net/ipv4/ip_sockglue.c:1259
>>
>> which lock already depends on the new lock.
>>
>>
>> the existing dependency chain (in reverse order) is:
>>
>> -> #1 (sk_lock-AF_INET){+.+.}:
>>lock_sock_nested+0xc2/0x110 net/core/sock.c:2780
>>lock_sock include/net/sock.h:1461 [inline]
>>do_ip_getsockopt+0x1b3/0x2170 net/ipv4/ip_sockglue.c:1335
>>ip_getsockopt+0x90/0x220 net/ipv4/ip_sockglue.c:1566
>>tcp_getsockopt+0x82/0xd0 net/ipv4/tcp.c:3359
>>sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2937
>>SYSC_getsockopt net/socket.c:1880 [inline]
>>SyS_getsockopt+0x178/0x340 net/socket.c:1862
>>entry_SYSCALL_64_fastpath+0x29/0xa0
>>
>> -> #0 (rtnl_mutex){+.+.}:
>>lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920
>>__mutex_lock_common kernel/locking/mutex.c:756 [inline]
>>__mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893
>>mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
>>rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
>>register_netdevice_notifier+0xad/0x860 net/core/dev.c:1607
>>tee_tg_check+0x1a0/0x280 net/netfilter/xt_TEE.c:106
>>xt_check_target+0x22c/0x7d0 net/netfilter/x_tables.c:845
>>check_target net/ipv4/netfilter/ip_tables.c:513 [inline]
>>find_check_entry.isra.8+0x8c8/0xcb0
>> net/ipv4/netfilter/ip_tables.c:554
>>translate_table+0xed1/0x1610 net/ipv4/netfilter/ip_tables.c:725
>>do_replace net/ipv4/netfilter/ip_tables.c:1141 [inline]
>>do_ipt_set_ctl+0x370/0x5f0 net/ipv4/netfilter/ip_tables.c:1675
>>nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
>>nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115
>>ip_setsockopt+0xa1/0xb0 net/ipv4/ip_sockglue.c:1260
>>sctp_setsockopt+0x2b6/0x61d0 net/sctp/socket.c:4104
>>sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2978
>>SYSC_setsockopt net/socket.c:1849 [inline]
>>SyS_setsockopt+0x189/0x360 net/socket.c:1828
>>entry_SYSCALL_64_fastpath+0x29/0xa0
>>
>> other info that might help us debug this:
>>
>> Possible unsafe locking scenario:
>>
>>CPU0CPU1
>>
>> lock(sk_lock-AF_INET);
>>lock(rtnl_mutex);
>>lock(sk_lock-AF_INET);
>> lock(rtnl_mutex);
>>
>> *** DEADLOCK ***
>>
>> 1 lock held by syzkaller681093/4124:
>> #0: (sk_lock-AF_INET){+.+.}, at: [<51813e83>] lock_sock
>> include/net/sock.h:1461 [inline]
>> #0: (sk_lock-AF_INET){+.+.}, at: [<51813e83>]
>> ip_setsockopt+0x8c/0xb0 net/ipv4/ip_sockglue.c:1259
>>
>> stack backtrace:
>> CPU: 0 PID: 4124 Comm: syzkaller681093 Not tainted 4.15.0+ #290
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> Google 01/01/2011
>> Call Trace:
>> __dump_stack lib/dump_stack.c:17 [inline]
>> dump_stack+0x194/0x257 lib/dump_stack.c:53
>> print_circular_bug.isra.38+0x2cd/0x2dc kernel/locking/lockdep.c:1223
>> check_prev_add kernel/locking/lockdep.c:1863 [inline]
>> check_prevs_add kernel/locking/lockdep.c:1976 [inline]
>> validate_chain kernel/locking/lockdep.c:2417 [inline]
>> __lock_acquire+0x30a8/0x3e00 kernel/locking/lockdep.c:3431
>> lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920
>> __mutex_lock_common kernel/locking/mutex.c:756 [inline]
>> __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893
>> mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
>> rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
>> register_netdevice_
Re: possible deadlock in rtnl_lock (2)
On Thu, Feb 1, 2018 at 7:58 PM, syzbot
wrote:
> Hello,
>
> syzbot hit the following crash on upstream commit
> 255442c93843f52b6891b21d0b485bf2c97f93c3 (Thu Feb 1 03:25:25 2018 +)
> Merge tag 'docs-4.16' of git://git.lwn.net/linux
>
> So far this crash happened 1587 times on net-next, upstream.
> C reproducer is attached.
> syzkaller reproducer is attached.
> Raw console output is attached.
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+61e4972c2b1d5e08a...@syzkaller.appspotmail.com
> It will help syzbot understand when the bug is fixed. See footer for
> details.
> If you forward the report, please keep this part and the footer.
>
>
> ==
> WARNING: possible circular locking dependency detected
> 4.15.0+ #290 Not tainted
> --
> syzkaller681093/4124 is trying to acquire lock:
> (rtnl_mutex){+.+.}, at: [] rtnl_lock+0x17/0x20
> net/core/rtnetlink.c:74
>
> but task is already holding lock:
> (sk_lock-AF_INET){+.+.}, at: [<51813e83>] lock_sock
> include/net/sock.h:1461 [inline]
> (sk_lock-AF_INET){+.+.}, at: [<51813e83>] ip_setsockopt+0x8c/0xb0
> net/ipv4/ip_sockglue.c:1259
>
> which lock already depends on the new lock.
>
>
> the existing dependency chain (in reverse order) is:
>
> -> #1 (sk_lock-AF_INET){+.+.}:
>lock_sock_nested+0xc2/0x110 net/core/sock.c:2780
>lock_sock include/net/sock.h:1461 [inline]
>do_ip_getsockopt+0x1b3/0x2170 net/ipv4/ip_sockglue.c:1335
>ip_getsockopt+0x90/0x220 net/ipv4/ip_sockglue.c:1566
>tcp_getsockopt+0x82/0xd0 net/ipv4/tcp.c:3359
>sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2937
>SYSC_getsockopt net/socket.c:1880 [inline]
>SyS_getsockopt+0x178/0x340 net/socket.c:1862
>entry_SYSCALL_64_fastpath+0x29/0xa0
>
> -> #0 (rtnl_mutex){+.+.}:
>lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920
>__mutex_lock_common kernel/locking/mutex.c:756 [inline]
>__mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893
>mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
>rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
>register_netdevice_notifier+0xad/0x860 net/core/dev.c:1607
>tee_tg_check+0x1a0/0x280 net/netfilter/xt_TEE.c:106
>xt_check_target+0x22c/0x7d0 net/netfilter/x_tables.c:845
>check_target net/ipv4/netfilter/ip_tables.c:513 [inline]
>find_check_entry.isra.8+0x8c8/0xcb0
> net/ipv4/netfilter/ip_tables.c:554
>translate_table+0xed1/0x1610 net/ipv4/netfilter/ip_tables.c:725
>do_replace net/ipv4/netfilter/ip_tables.c:1141 [inline]
>do_ipt_set_ctl+0x370/0x5f0 net/ipv4/netfilter/ip_tables.c:1675
>nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
>nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115
>ip_setsockopt+0xa1/0xb0 net/ipv4/ip_sockglue.c:1260
>sctp_setsockopt+0x2b6/0x61d0 net/sctp/socket.c:4104
>sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2978
>SYSC_setsockopt net/socket.c:1849 [inline]
>SyS_setsockopt+0x189/0x360 net/socket.c:1828
>entry_SYSCALL_64_fastpath+0x29/0xa0
>
> other info that might help us debug this:
>
> Possible unsafe locking scenario:
>
>CPU0CPU1
>
> lock(sk_lock-AF_INET);
>lock(rtnl_mutex);
>lock(sk_lock-AF_INET);
> lock(rtnl_mutex);
>
> *** DEADLOCK ***
>
> 1 lock held by syzkaller681093/4124:
> #0: (sk_lock-AF_INET){+.+.}, at: [<51813e83>] lock_sock
> include/net/sock.h:1461 [inline]
> #0: (sk_lock-AF_INET){+.+.}, at: [<51813e83>]
> ip_setsockopt+0x8c/0xb0 net/ipv4/ip_sockglue.c:1259
>
> stack backtrace:
> CPU: 0 PID: 4124 Comm: syzkaller681093 Not tainted 4.15.0+ #290
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:17 [inline]
> dump_stack+0x194/0x257 lib/dump_stack.c:53
> print_circular_bug.isra.38+0x2cd/0x2dc kernel/locking/lockdep.c:1223
> check_prev_add kernel/locking/lockdep.c:1863 [inline]
> check_prevs_add kernel/locking/lockdep.c:1976 [inline]
> validate_chain kernel/locking/lockdep.c:2417 [inline]
> __lock_acquire+0x30a8/0x3e00 kernel/locking/lockdep.c:3431
> lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920
> __mutex_lock_common kernel/locking/mutex.c:756 [inline]
> __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893
> mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
> rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
> register_netdevice_notifier+0xad/0x860 net/core/dev.c:1607
> tee_tg_check+0x1a0/0x280 net/netfilter/xt_TEE.c:106
> xt_check_target+0x22c/0x7d0 net/netfilter/x_tables.c:845
> check_t
