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Miller" , Jakub Kicinski , Paolo Abeni , Simon Horman , Stanislav Fomichev , netdev@vger.kernel.org, eric.dumazet@gmail.com, syzbot Subject: Re: [PATCH net-next] hamradio: use netdev_lockdep_set_classes() helper Message-ID: References: <20250307160358.3153859-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250307160358.3153859-1-edumazet@google.com> On 03/07, Eric Dumazet wrote: > It is time to use netdev_lockdep_set_classes() in bpqether.c > > List of related commits: > > 0bef512012b1 ("net: add netdev_lockdep_set_classes() to virtual drivers") > c74e1039912e ("net: bridge: use netdev_lockdep_set_classes()") > 9a3c93af5491 ("vlan: use netdev_lockdep_set_classes()") > 0d7dd798fd89 ("net: ipvlan: call netdev_lockdep_set_classes()") > 24ffd752007f ("net: macvlan: call netdev_lockdep_set_classes()") > 78e7a2ae8727 ("net: vrf: call netdev_lockdep_set_classes()") > d3fff6c443fe ("net: add netdev_lockdep_set_classes() helper") > > syzbot reported: > > WARNING: possible recursive locking detected > 6.14.0-rc5-syzkaller-01064-g2525e16a2bae #0 Not tainted > > dhcpcd/5501 is trying to acquire lock: > ffff8880797e2d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] > ffff8880797e2d28 (&dev->lock){+.+.}-{4:4}, at: register_netdevice+0x12d8/0x1b70 net/core/dev.c:11008 > > but task is already holding lock: > ffff88802e530d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] > ffff88802e530d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/linux/netdevice.h:2804 [inline] > ffff88802e530d28 (&dev->lock){+.+.}-{4:4}, at: dev_change_flags+0x120/0x270 net/core/dev_api.c:65 > > other info that might help us debug this: > Possible unsafe locking scenario: > > CPU0 > ---- > lock(&dev->lock); > lock(&dev->lock); > > *** DEADLOCK *** > > May be due to missing lock nesting notation > > 2 locks held by dhcpcd/5501: > #0: ffffffff8fed6848 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] > #0: ffffffff8fed6848 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x34c/0x1d80 net/ipv4/devinet.c:1121 > #1: ffff88802e530d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] > #1: ffff88802e530d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/linux/netdevice.h:2804 [inline] > #1: ffff88802e530d28 (&dev->lock){+.+.}-{4:4}, at: dev_change_flags+0x120/0x270 net/core/dev_api.c:65 > > stack backtrace: > CPU: 1 UID: 0 PID: 5501 Comm: dhcpcd Not tainted 6.14.0-rc5-syzkaller-01064-g2525e16a2bae #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 > Call Trace: > > __dump_stack lib/dump_stack.c:94 [inline] > dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 > print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3039 > check_deadlock kernel/locking/lockdep.c:3091 [inline] > validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3893 > __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 > __mutex_lock_common kernel/locking/mutex.c:585 [inline] > __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 > netdev_lock include/linux/netdevice.h:2765 [inline] > register_netdevice+0x12d8/0x1b70 net/core/dev.c:11008 > bpq_new_device drivers/net/hamradio/bpqether.c:499 [inline] > bpq_device_event+0x4b1/0x8d0 drivers/net/hamradio/bpqether.c:542 > notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85 > __dev_notify_flags+0x207/0x400 > netif_change_flags+0xf0/0x1a0 net/core/dev.c:9442 > dev_change_flags+0x146/0x270 net/core/dev_api.c:66 > devinet_ioctl+0xea2/0x1d80 net/ipv4/devinet.c:1200 > inet_ioctl+0x3d7/0x4f0 net/ipv4/af_inet.c:1001 > sock_do_ioctl+0x158/0x460 net/socket.c:1190 > sock_ioctl+0x626/0x8e0 net/socket.c:1309 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:906 [inline] > __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Fixes: 7e4d784f5810 ("net: hold netdev instance lock during rtnetlink operations") > Reported-by: syzbot > Signed-off-by: Eric Dumazet Acked-by: Stanislav Fomichev