Extracting prog: 5m17.81857385s Minimizing prog: 20m59.980054867s Simplifying prog options: 19m4.713358754s Extracting C: 5m51.851569262s Simplifying C: 0s extracting reproducer from 65 programs testing a last program of every proc single: executing 17 programs separately with timeout 6m0s testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route-socket$can_j1939-ioctl$ifreq_SIOCGIFINDEX_vcan-bind$can_j1939-setsockopt$sock_int-sendmsg$inet-socket$can_j1939-setsockopt$SO_J1939_FILTER-ioctl$ifreq_SIOCGIFINDEX_vcan-sendmsg$nl_route_sched detailed listing: executing program 0: r0 = socket$nl_route(0x10, 0x3, 0x0) r1 = socket$can_j1939(0x1d, 0x2, 0x7) ioctl$ifreq_SIOCGIFINDEX_vcan(r1, 0x8933, &(0x7f00000000c0)={'vcan0\x00', 0x0}) bind$can_j1939(r1, &(0x7f0000000100)={0x1d, r2, 0x0, {0x0, 0x0, 0x4}, 0x1}, 0x18) setsockopt$sock_int(r1, 0x1, 0x6, &(0x7f0000000040)=0x1, 0x4) sendmsg$inet(r1, &(0x7f0000000080)={0x0, 0x0, &(0x7f00000003c0)=[{&(0x7f0000000400)="81b641f1f3843704b6", 0x9}], 0x1}, 0x48005) r3 = socket$can_j1939(0x1d, 0x2, 0x7) setsockopt$SO_J1939_FILTER(r1, 0x6b, 0x1, &(0x7f00000001c0)=[{0x2, 0x2, {0x1, 0xff, 0x1}, {0x2, 0x0, 0x2}, 0x1, 0xfe}], 0x20) ioctl$ifreq_SIOCGIFINDEX_vcan(r3, 0x8933, &(0x7f0000000000)={'vcan0\x00', 0x0}) sendmsg$nl_route_sched(r0, &(0x7f00000002c0)={0x0, 0xffc3, &(0x7f0000000240)={&(0x7f0000000780)=@newtfilter={0x24, 0x11, 0x1, 0x70bd2b, 0x0, {0x0, 0x0, 0x74, r4, {0xfff8, 0x4}, {0x0, 0xe}, {0xfff2, 0xffff}}}, 0x24}, 0x1, 0xf0ffffffffffff}, 0x840) program crashed: possible deadlock in register_netdevice single: successfully extracted reproducer found reproducer with 10 syscalls minimizing guilty program testing program (duration=7m31.456673316s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route-socket$can_j1939-ioctl$ifreq_SIOCGIFINDEX_vcan-bind$can_j1939-setsockopt$sock_int-sendmsg$inet-socket$can_j1939-setsockopt$SO_J1939_FILTER-ioctl$ifreq_SIOCGIFINDEX_vcan detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) r0 = socket$can_j1939(0x1d, 0x2, 0x7) ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f00000000c0)={'vcan0\x00', 0x0}) bind$can_j1939(r0, &(0x7f0000000100)={0x1d, r1, 0x0, {0x0, 0x0, 0x4}, 0x1}, 0x18) setsockopt$sock_int(r0, 0x1, 0x6, &(0x7f0000000040)=0x1, 0x4) sendmsg$inet(r0, &(0x7f0000000080)={0x0, 0x0, &(0x7f00000003c0)=[{&(0x7f0000000400)="81b641f1f3843704b6", 0x9}], 0x1}, 0x48005) r2 = socket$can_j1939(0x1d, 0x2, 0x7) setsockopt$SO_J1939_FILTER(r0, 0x6b, 0x1, &(0x7f00000001c0)=[{0x2, 0x2, {0x1, 0xff, 0x1}, {0x2, 0x0, 0x2}, 0x1, 0xfe}], 0x20) ioctl$ifreq_SIOCGIFINDEX_vcan(r2, 0x8933, &(0x7f0000000000)={'vcan0\x00'}) program crashed: possible deadlock in register_netdevice testing program (duration=7m31.456673316s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route-socket$can_j1939-ioctl$ifreq_SIOCGIFINDEX_vcan-bind$can_j1939-setsockopt$sock_int-sendmsg$inet-socket$can_j1939-setsockopt$SO_J1939_FILTER detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) r0 = socket$can_j1939(0x1d, 0x2, 0x7) ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f00000000c0)={'vcan0\x00', 0x0}) bind$can_j1939(r0, &(0x7f0000000100)={0x1d, r1, 0x0, {0x0, 0x0, 0x4}, 0x1}, 0x18) setsockopt$sock_int(r0, 0x1, 0x6, &(0x7f0000000040)=0x1, 0x4) sendmsg$inet(r0, &(0x7f0000000080)={0x0, 0x0, &(0x7f00000003c0)=[{&(0x7f0000000400)="81b641f1f3843704b6", 0x9}], 0x1}, 0x48005) socket$can_j1939(0x1d, 0x2, 0x7) setsockopt$SO_J1939_FILTER(r0, 0x6b, 0x1, &(0x7f00000001c0)=[{0x2, 0x2, {0x1, 0xff, 0x1}, {0x2, 0x0, 0x2}, 0x1, 0xfe}], 0x20) program crashed: possible deadlock in register_netdevice testing program (duration=7m31.456673316s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route-socket$can_j1939-ioctl$ifreq_SIOCGIFINDEX_vcan-bind$can_j1939-setsockopt$sock_int-sendmsg$inet-socket$can_j1939 detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) r0 = socket$can_j1939(0x1d, 0x2, 0x7) ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f00000000c0)={'vcan0\x00', 0x0}) bind$can_j1939(r0, &(0x7f0000000100)={0x1d, r1, 0x0, {0x0, 0x0, 0x4}, 0x1}, 0x18) setsockopt$sock_int(r0, 0x1, 0x6, &(0x7f0000000040)=0x1, 0x4) sendmsg$inet(r0, &(0x7f0000000080)={0x0, 0x0, &(0x7f00000003c0)=[{&(0x7f0000000400)="81b641f1f3843704b6", 0x9}], 0x1}, 0x48005) socket$can_j1939(0x1d, 0x2, 0x7) program crashed: possible deadlock in register_netdevice testing program (duration=7m31.456673316s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route-socket$can_j1939-ioctl$ifreq_SIOCGIFINDEX_vcan-bind$can_j1939-setsockopt$sock_int-sendmsg$inet detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) r0 = socket$can_j1939(0x1d, 0x2, 0x7) ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f00000000c0)={'vcan0\x00', 0x0}) bind$can_j1939(r0, &(0x7f0000000100)={0x1d, r1, 0x0, {0x0, 0x0, 0x4}, 0x1}, 0x18) setsockopt$sock_int(r0, 0x1, 0x6, &(0x7f0000000040)=0x1, 0x4) sendmsg$inet(r0, &(0x7f0000000080)={0x0, 0x0, &(0x7f00000003c0)=[{&(0x7f0000000400)="81b641f1f3843704b6", 0x9}], 0x1}, 0x48005) program crashed: possible deadlock in register_netdevice testing program (duration=7m31.456673316s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route-socket$can_j1939-ioctl$ifreq_SIOCGIFINDEX_vcan-bind$can_j1939-setsockopt$sock_int detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) r0 = socket$can_j1939(0x1d, 0x2, 0x7) ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f00000000c0)={'vcan0\x00', 0x0}) bind$can_j1939(r0, &(0x7f0000000100)={0x1d, r1, 0x0, {0x0, 0x0, 0x4}, 0x1}, 0x18) setsockopt$sock_int(r0, 0x1, 0x6, &(0x7f0000000040)=0x1, 0x4) program crashed: possible deadlock in register_netdevice testing program (duration=7m31.456673316s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route-socket$can_j1939-ioctl$ifreq_SIOCGIFINDEX_vcan-bind$can_j1939 detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) r0 = socket$can_j1939(0x1d, 0x2, 0x7) ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f00000000c0)={'vcan0\x00', 0x0}) bind$can_j1939(r0, &(0x7f0000000100)={0x1d, r1, 0x0, {0x0, 0x0, 0x4}, 0x1}, 0x18) program crashed: possible deadlock in register_netdevice testing program (duration=7m31.456673316s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route-socket$can_j1939-ioctl$ifreq_SIOCGIFINDEX_vcan detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) r0 = socket$can_j1939(0x1d, 0x2, 0x7) ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f00000000c0)={'vcan0\x00'}) program crashed: possible deadlock in register_netdevice testing program (duration=7m31.456673316s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route-socket$can_j1939 detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) socket$can_j1939(0x1d, 0x2, 0x7) program crashed: possible deadlock in register_netdevice testing program (duration=7m31.456673316s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) program crashed: possible deadlock in register_netdevice extracting C reproducer testing compiled C program (duration=7m31.456673316s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route program crashed: no output from test machine a never seen crash title: no output from test machine, ignore simplifying guilty program options testing program (duration=7m31.456673316s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) program crashed: possible deadlock in register_netdevice extracting C reproducer testing compiled C program (duration=7m31.456673316s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route program crashed: no output from test machine a never seen crash title: no output from test machine, ignore testing program (duration=7m31.456673316s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route detailed listing: executing program 0: socket$nl_route(0x10, 0x3, 0x0) program crashed: possible deadlock in register_netdevice extracting C reproducer testing compiled C program (duration=7m31.456673316s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$nl_route program crashed: no output from test machine a never seen crash title: no output from test machine, ignore reproducing took 51m44.63398399s repro crashed as (corrupted=false): ============================================ WARNING: possible recursive locking detected 6.14.0-rc5-syzkaller-01140-ge2537326e3b6 #0 Not tainted -------------------------------------------- dhcpcd/5502 is trying to acquire lock: ffff88802f98cd28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] ffff88802f98cd28 (&dev->lock){+.+.}-{4:4}, at: register_netdevice+0x12d8/0x1b70 net/core/dev.c:11008 but task is already holding lock: ffff88807bc44d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] ffff88807bc44d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/linux/netdevice.h:2804 [inline] ffff88807bc44d28 (&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/5502: #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: ffff88807bc44d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] #1: ffff88807bc44d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/linux/netdevice.h:2804 [inline] #1: ffff88807bc44d28 (&dev->lock){+.+.}-{4:4}, at: dev_change_flags+0x120/0x270 net/core/dev_api.c:65 stack backtrace: CPU: 0 UID: 0 PID: 5502 Comm: dhcpcd Not tainted 6.14.0-rc5-syzkaller-01140-ge2537326e3b6 #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 RIP: 0033:0x7f34f5b5cd49 Code: 5c c3 48 8d 44 24 08 48 89 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 b8 10 00 00 00 c7 44 24 b8 10 00 00 00 0f 05 <41> 89 c0 3d 00 f0 ff ff 76 10 48 8b 15 ae 60 0d 00 f7 d8 41 83 c8 RSP: 002b:00007ffc54dfb048 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f34f5a8e6c0 RCX: 00007f34f5b5cd49 RDX: 00007ffc54e0b238 RSI: 0000000000008914 RDI: 000000000000000e RBP: 00007ffc54e1b3f8 R08: 00007ffc54e0b1f8 R09: 00007ffc54e0b1a8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc54e0b238 R14: 0000000000000028 R15: 0000000000008914 final repro crashed as (corrupted=false): ============================================ WARNING: possible recursive locking detected 6.14.0-rc5-syzkaller-01140-ge2537326e3b6 #0 Not tainted -------------------------------------------- dhcpcd/5502 is trying to acquire lock: ffff88802f98cd28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] ffff88802f98cd28 (&dev->lock){+.+.}-{4:4}, at: register_netdevice+0x12d8/0x1b70 net/core/dev.c:11008 but task is already holding lock: ffff88807bc44d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] ffff88807bc44d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/linux/netdevice.h:2804 [inline] ffff88807bc44d28 (&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/5502: #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: ffff88807bc44d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] #1: ffff88807bc44d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/linux/netdevice.h:2804 [inline] #1: ffff88807bc44d28 (&dev->lock){+.+.}-{4:4}, at: dev_change_flags+0x120/0x270 net/core/dev_api.c:65 stack backtrace: CPU: 0 UID: 0 PID: 5502 Comm: dhcpcd Not tainted 6.14.0-rc5-syzkaller-01140-ge2537326e3b6 #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 RIP: 0033:0x7f34f5b5cd49 Code: 5c c3 48 8d 44 24 08 48 89 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 b8 10 00 00 00 c7 44 24 b8 10 00 00 00 0f 05 <41> 89 c0 3d 00 f0 ff ff 76 10 48 8b 15 ae 60 0d 00 f7 d8 41 83 c8 RSP: 002b:00007ffc54dfb048 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f34f5a8e6c0 RCX: 00007f34f5b5cd49 RDX: 00007ffc54e0b238 RSI: 0000000000008914 RDI: 000000000000000e RBP: 00007ffc54e1b3f8 R08: 00007ffc54e0b1f8 R09: 00007ffc54e0b1a8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc54e0b238 R14: 0000000000000028 R15: 0000000000008914