From: Stanislav Fomichev <stfomichev@gmail.com>
To: syzbot <syzbot+58c65777e7d41ac833a9@syzkaller.appspotmail.com>
Cc: davem@davemloft.net, edumazet@google.com, horms@kernel.org,
kuba@kernel.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, pabeni@redhat.com,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [net?] possible deadlock in dev_set_promiscuity
Date: Mon, 2 Jun 2025 18:49:49 -0700 [thread overview]
Message-ID: <aD5UvenmZ4MMXYzT@mini-arch> (raw)
In-Reply-To: <683d556f.a00a0220.d8eae.0046.GAE@google.com>
On 06/02, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 90b83efa6701 Merge tag 'bpf-next-6.16' of git://git.kernel..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=135adbf4580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=262b2977ef00756b
> dashboard link: https://syzkaller.appspot.com/bug?extid=58c65777e7d41ac833a9
> compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
> userspace arch: i386
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/2dccf70158c7/disk-90b83efa.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/e7a2b208c541/vmlinux-90b83efa.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/022501a5f90a/bzImage-90b83efa.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+58c65777e7d41ac833a9@syzkaller.appspotmail.com
>
> batadv0: entered promiscuous mode
> team0: entered promiscuous mode
> team_slave_0: entered promiscuous mode
> macvlan2: entered promiscuous mode
> bond0: entered promiscuous mode
> ======================================================
> WARNING: possible circular locking dependency detected
> 6.15.0-syzkaller-07774-g90b83efa6701 #0 Not tainted
> ------------------------------------------------------
> syz.1.1497/11860 is trying to acquire lock:
> ffff8880314e4d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2756 [inline]
> ffff8880314e4d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
> ffff8880314e4d30 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: dev_set_promiscuity+0x10e/0x260 net/core/dev_api.c:286
>
> but task is already holding lock:
> ffff88805cd74e00 (team->team_lock_key#5){+.+.}-{4:4}, at: team_change_rx_flags+0x38/0x220 drivers/net/team/team_core.c:1781
>
> which lock already depends on the new lock.
>
>
> the existing dependency chain (in reverse order) is:
>
> -> #1 (team->team_lock_key#5){+.+.}-{4:4}:
> lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
> __mutex_lock_common kernel/locking/mutex.c:601 [inline]
> __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
> team_port_change_check drivers/net/team/team_core.c:2966 [inline]
> team_device_event+0x182/0xa20 drivers/net/team/team_core.c:2992
> notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
> call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
> call_netdevice_notifiers net/core/dev.c:2282 [inline]
> dev_close_many+0x29c/0x410 net/core/dev.c:1785
> vlan_device_event+0x1748/0x1d00 net/8021q/vlan.c:449
> notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
> call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
> call_netdevice_notifiers net/core/dev.c:2282 [inline]
> __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
> netif_change_flags+0xe8/0x1a0 net/core/dev.c:9526
> do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3141
> rtnl_changelink net/core/rtnetlink.c:3759 [inline]
> __rtnl_newlink net/core/rtnetlink.c:3918 [inline]
> rtnl_newlink+0x160b/0x1c70 net/core/rtnetlink.c:4055
> rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6944
> netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2534
> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339
> netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
> sock_sendmsg_nosec net/socket.c:712 [inline]
> __sock_sendmsg+0x219/0x270 net/socket.c:727
> ____sys_sendmsg+0x505/0x830 net/socket.c:2566
> ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
> __sys_sendmsg+0x164/0x220 net/socket.c:2652
> do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
> __do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306
> do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
> entry_SYSENTER_compat_after_hwframe+0x84/0x8e
>
> -> #0 (&dev_instance_lock_key#20){+.+.}-{4:4}:
> check_prev_add kernel/locking/lockdep.c:3168 [inline]
> check_prevs_add kernel/locking/lockdep.c:3287 [inline]
> validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
> __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
> lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
> __mutex_lock_common kernel/locking/mutex.c:601 [inline]
> __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
> netdev_lock include/linux/netdevice.h:2756 [inline]
> netdev_lock_ops include/net/netdev_lock.h:42 [inline]
> dev_set_promiscuity+0x10e/0x260 net/core/dev_api.c:286
> bond_set_promiscuity drivers/net/bonding/bond_main.c:919 [inline]
> bond_change_rx_flags+0x219/0x690 drivers/net/bonding/bond_main.c:4738
> dev_change_rx_flags net/core/dev.c:9241 [inline]
> __dev_set_promiscuity+0x534/0x740 net/core/dev.c:9285
> netif_set_promiscuity+0x50/0xe0 net/core/dev.c:9305
> dev_set_promiscuity+0x126/0x260 net/core/dev_api.c:287
> dev_change_rx_flags net/core/dev.c:9241 [inline]
> __dev_set_promiscuity+0x534/0x740 net/core/dev.c:9285
> netif_set_promiscuity+0x50/0xe0 net/core/dev.c:9305
> dev_set_promiscuity+0x126/0x260 net/core/dev_api.c:287
> team_change_rx_flags+0x123/0x220 drivers/net/team/team_core.c:1785
> dev_change_rx_flags net/core/dev.c:9241 [inline]
> __dev_set_promiscuity+0x534/0x740 net/core/dev.c:9285
> netif_set_promiscuity+0x50/0xe0 net/core/dev.c:9305
> dev_set_promiscuity+0x126/0x260 net/core/dev_api.c:287
> hsr_portdev_setup net/hsr/hsr_slave.c:148 [inline]
> hsr_add_port+0x549/0x890 net/hsr/hsr_slave.c:202
> hsr_dev_finalize+0x6c4/0xaa0 net/hsr/hsr_device.c:760
> hsr_newlink+0x7d7/0x940 net/hsr/hsr_netlink.c:122
> rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3823
> __rtnl_newlink net/core/rtnetlink.c:3940 [inline]
> rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4055
> rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6944
> netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2534
> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339
> netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
> sock_sendmsg_nosec net/socket.c:712 [inline]
> __sock_sendmsg+0x219/0x270 net/socket.c:727
> ____sys_sendmsg+0x505/0x830 net/socket.c:2566
> ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
> __sys_sendmsg+0x164/0x220 net/socket.c:2652
> do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
> __do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306
> do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
> entry_SYSENTER_compat_after_hwframe+0x84/0x8e
>
> other info that might help us debug this:
>
> Possible unsafe locking scenario:
>
> CPU0 CPU1
> ---- ----
> lock(team->team_lock_key#5);
> lock(&dev_instance_lock_key#20);
> lock(team->team_lock_key#5);
> lock(&dev_instance_lock_key#20);
>
> *** DEADLOCK ***
>
> 3 locks held by syz.1.1497/11860:
> #0: ffffffff8fa2cd70 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
> #0: ffffffff8fa2cd70 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
> #0: ffffffff8fa2cd70 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
> #1: ffffffff8f50a808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
> #1: ffffffff8f50a808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
> #1: ffffffff8f50a808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4054
> #2: ffff88805cd74e00 (team->team_lock_key#5){+.+.}-{4:4}, at: team_change_rx_flags+0x38/0x220 drivers/net/team/team_core.c:1781
>
> stack backtrace:
> CPU: 1 UID: 0 PID: 11860 Comm: syz.1.1497 Not tainted 6.15.0-syzkaller-07774-g90b83efa6701 #0 PREEMPT(full)
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
> Call Trace:
> <TASK>
> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
> print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2046
> check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2178
> check_prev_add kernel/locking/lockdep.c:3168 [inline]
> check_prevs_add kernel/locking/lockdep.c:3287 [inline]
> validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
> __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
> lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
> __mutex_lock_common kernel/locking/mutex.c:601 [inline]
> __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
> netdev_lock include/linux/netdevice.h:2756 [inline]
> netdev_lock_ops include/net/netdev_lock.h:42 [inline]
> dev_set_promiscuity+0x10e/0x260 net/core/dev_api.c:286
> bond_set_promiscuity drivers/net/bonding/bond_main.c:919 [inline]
> bond_change_rx_flags+0x219/0x690 drivers/net/bonding/bond_main.c:4738
> dev_change_rx_flags net/core/dev.c:9241 [inline]
> __dev_set_promiscuity+0x534/0x740 net/core/dev.c:9285
> netif_set_promiscuity+0x50/0xe0 net/core/dev.c:9305
> dev_set_promiscuity+0x126/0x260 net/core/dev_api.c:287
> dev_change_rx_flags net/core/dev.c:9241 [inline]
> __dev_set_promiscuity+0x534/0x740 net/core/dev.c:9285
> netif_set_promiscuity+0x50/0xe0 net/core/dev.c:9305
> dev_set_promiscuity+0x126/0x260 net/core/dev_api.c:287
> team_change_rx_flags+0x123/0x220 drivers/net/team/team_core.c:1785
> dev_change_rx_flags net/core/dev.c:9241 [inline]
> __dev_set_promiscuity+0x534/0x740 net/core/dev.c:9285
> netif_set_promiscuity+0x50/0xe0 net/core/dev.c:9305
> dev_set_promiscuity+0x126/0x260 net/core/dev_api.c:287
> hsr_portdev_setup net/hsr/hsr_slave.c:148 [inline]
> hsr_add_port+0x549/0x890 net/hsr/hsr_slave.c:202
> hsr_dev_finalize+0x6c4/0xaa0 net/hsr/hsr_device.c:760
> hsr_newlink+0x7d7/0x940 net/hsr/hsr_netlink.c:122
> rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3823
> __rtnl_newlink net/core/rtnetlink.c:3940 [inline]
> rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4055
> rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6944
> netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2534
> netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339
> netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
> sock_sendmsg_nosec net/socket.c:712 [inline]
> __sock_sendmsg+0x219/0x270 net/socket.c:727
> ____sys_sendmsg+0x505/0x830 net/socket.c:2566
> ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
> __sys_sendmsg+0x164/0x220 net/socket.c:2652
> do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
> __do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306
> do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
> entry_SYSENTER_compat_after_hwframe+0x84/0x8e
> RIP: 0023:0xf705e539
I wonder whether mutex_lock(lock: &team->lock) is really needed in
team_change_rx_flags. I did add it while converting from rcu. Adding
to that list happens in do_setlink (rtnl) and the same for the
callers of dev_change_rx_flags. (and bonding driver doesn't do any
locking either). Or hope that https://lore.kernel.org/netdev/d4047311-5644-4884-84c0-059bbb9e98ee@I-love.SAKURA.ne.jp/
happens soon?
prev parent reply other threads:[~2025-06-03 1:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-02 7:40 [syzbot] [net?] possible deadlock in dev_set_promiscuity syzbot
2025-06-03 1:49 ` Stanislav Fomichev [this message]
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