syzbot


possible deadlock in pppoe_device_event

Status: auto-obsoleted due to no activity on 2023/06/17 17:51
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+0ba232cc2253a6604b95@syzkaller.appspotmail.com
First crash: 450d, last: 425d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] possible deadlock in pppoe_device_event 0 (1) 2023/01/28 01:13

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc6-syzkaller-00273-g837c07cf68fe #0 Not tainted
------------------------------------------------------
syz-executor.3/23882 is trying to acquire lock:
ffff88802f328130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1725 [inline]
ffff88802f328130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppoe_flush_dev drivers/net/ppp/pppoe.c:304 [inline]
ffff88802f328130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppoe_device_event+0x329/0x980 drivers/net/ppp/pppoe.c:346

but task is already holding lock:
ffffffff8e0b5750 (dev_addr_sem){++++}-{3:3}, at: dev_set_mac_address_user+0x23/0x50 net/core/dev.c:8804

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (dev_addr_sem){++++}-{3:3}:
       down_write+0x94/0x220 kernel/locking/rwsem.c:1562
       dev_set_mac_address_user+0x23/0x50 net/core/dev.c:8804
       do_setlink+0x18c4/0x3bb0 net/core/rtnetlink.c:2775
       __rtnl_newlink+0xd69/0x1840 net/core/rtnetlink.c:3590
       rtnl_newlink+0x68/0xa0 net/core/rtnetlink.c:3637
       rtnetlink_rcv_msg+0x43e/0xca0 net/core/rtnetlink.c:6141
       netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2574
       netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
       netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365
       netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1942
       sock_sendmsg_nosec net/socket.c:714 [inline]
       sock_sendmsg+0xd3/0x120 net/socket.c:734
       __sys_sendto+0x23a/0x340 net/socket.c:2117
       __do_sys_sendto net/socket.c:2129 [inline]
       __se_sys_sendto net/socket.c:2125 [inline]
       __x64_sys_sendto+0xe1/0x1b0 net/socket.c:2125
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #2 (rtnl_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747
       prb_calc_retire_blk_tmo+0x7d/0x1e0 net/packet/af_packet.c:576
       init_prb_bdqc net/packet/af_packet.c:634 [inline]
       packet_set_ring+0x158f/0x1980 net/packet/af_packet.c:4439
       packet_setsockopt+0x1a32/0x3a30 net/packet/af_packet.c:3808
       __sys_setsockopt+0x2c6/0x5b0 net/socket.c:2246
       __do_sys_setsockopt net/socket.c:2257 [inline]
       __se_sys_setsockopt net/socket.c:2254 [inline]
       __x64_sys_setsockopt+0xbe/0x160 net/socket.c:2254
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (sk_lock-AF_PACKET){+.+.}-{0:0}:
       lock_sock_nested+0x3a/0xf0 net/core/sock.c:3470
       lock_sock include/net/sock.h:1725 [inline]
       l2tp_tunnel_register+0x2aa/0x11e0 net/l2tp/l2tp_core.c:1483
       pppol2tp_connect+0xcdc/0x1a10 net/l2tp/l2tp_ppp.c:723
       __sys_connect_file+0x153/0x1a0 net/socket.c:1976
       __sys_connect+0x165/0x1a0 net/socket.c:1993
       __do_sys_connect net/socket.c:2003 [inline]
       __se_sys_connect net/socket.c:2000 [inline]
       __x64_sys_connect+0x73/0xb0 net/socket.c:2000
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (sk_lock-AF_PPPOX){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain kernel/locking/lockdep.c:3831 [inline]
       __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
       lock_acquire kernel/locking/lockdep.c:5668 [inline]
       lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
       lock_sock_nested+0x3a/0xf0 net/core/sock.c:3470
       lock_sock include/net/sock.h:1725 [inline]
       pppoe_flush_dev drivers/net/ppp/pppoe.c:304 [inline]
       pppoe_device_event+0x329/0x980 drivers/net/ppp/pppoe.c:346
       notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
       call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1944
       call_netdevice_notifiers_extack net/core/dev.c:1982 [inline]
       call_netdevice_notifiers net/core/dev.c:1996 [inline]
       dev_set_mac_address+0x2d7/0x3e0 net/core/dev.c:8791
       bond_set_mac_address+0x359/0x7a0 drivers/net/bonding/bond_main.c:4743
       dev_set_mac_address+0x26b/0x3e0 net/core/dev.c:8787
       dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8805
       do_setlink+0x18c4/0x3bb0 net/core/rtnetlink.c:2775
       __rtnl_newlink+0xd69/0x1840 net/core/rtnetlink.c:3590
       rtnl_newlink+0x68/0xa0 net/core/rtnetlink.c:3637
       rtnetlink_rcv_msg+0x43e/0xca0 net/core/rtnetlink.c:6141
       netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2574
       netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
       netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365
       netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1942
       sock_sendmsg_nosec net/socket.c:714 [inline]
       sock_sendmsg+0xd3/0x120 net/socket.c:734
       ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
       ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
       __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  sk_lock-AF_PPPOX --> rtnl_mutex --> dev_addr_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(dev_addr_sem);
                               lock(rtnl_mutex);
                               lock(dev_addr_sem);
  lock(sk_lock-AF_PPPOX);

 *** DEADLOCK ***

2 locks held by syz-executor.3/23882:
 #0: ffffffff8e0c2528 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:75 [inline]
 #0: ffffffff8e0c2528 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3e9/0xca0 net/core/rtnetlink.c:6138
 #1: ffffffff8e0b5750 (dev_addr_sem){++++}-{3:3}, at: dev_set_mac_address_user+0x23/0x50 net/core/dev.c:8804

stack backtrace:
CPU: 0 PID: 23882 Comm: syz-executor.3 Not tainted 6.2.0-rc6-syzkaller-00273-g837c07cf68fe #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain kernel/locking/lockdep.c:3831 [inline]
 __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
 lock_acquire kernel/locking/lockdep.c:5668 [inline]
 lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
 lock_sock_nested+0x3a/0xf0 net/core/sock.c:3470
 lock_sock include/net/sock.h:1725 [inline]
 pppoe_flush_dev drivers/net/ppp/pppoe.c:304 [inline]
 pppoe_device_event+0x329/0x980 drivers/net/ppp/pppoe.c:346
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1944
 call_netdevice_notifiers_extack net/core/dev.c:1982 [inline]
 call_netdevice_notifiers net/core/dev.c:1996 [inline]
 dev_set_mac_address+0x2d7/0x3e0 net/core/dev.c:8791
 bond_set_mac_address+0x359/0x7a0 drivers/net/bonding/bond_main.c:4743
 dev_set_mac_address+0x26b/0x3e0 net/core/dev.c:8787
 dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8805
 do_setlink+0x18c4/0x3bb0 net/core/rtnetlink.c:2775
 __rtnl_newlink+0xd69/0x1840 net/core/rtnetlink.c:3590
 rtnl_newlink+0x68/0xa0 net/core/rtnetlink.c:3637
 rtnetlink_rcv_msg+0x43e/0xca0 net/core/rtnetlink.c:6141
 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2574
 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
 netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365
 netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1942
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xd3/0x120 net/socket.c:734
 ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476
 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530
 __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f9b0008c0c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9b00e47168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f9b001abf80 RCX: 00007f9b0008c0c9
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f9b000e7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b002cfb1f R14: 00007f9b00e47300 R15: 0000000000022000
 </TASK>
device bond0 entered promiscuous mode
device bond_slave_0 entered promiscuous mode
device bond_slave_1 entered promiscuous mode

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/02/05 20:07 upstream 837c07cf68fe be607b78 .config console log report info ci-upstream-kasan-gce possible deadlock in pppoe_device_event
2023/01/24 01:11 upstream 7bf70dbb1882 9dfcf09c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce possible deadlock in pppoe_device_event
2023/02/17 17:51 upstream ec35307e18ba 3e7039f4 .config console log report info ci-upstream-kasan-gce-386 possible deadlock in pppoe_device_event
2023/02/15 03:19 upstream e1c04510f521 1d6b4af7 .config console log report info ci-upstream-kasan-gce-386 possible deadlock in pppoe_device_event
* Struck through repros no longer work on HEAD.