Extracting prog: 5m34.645186689s
Minimizing prog: 2m14.08981939s
Simplifying prog options: 18m23.527044551s
Extracting C: 5m35.084516948s
Simplifying C: 0s


extracting reproducer from 1 programs
testing a last program of every proc
single: executing 1 programs separately with timeout 30s
testing program (duration=30s, {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$netlink-sendmsg$nl_route
detailed listing:
executing program 0:
r0 = socket$netlink(0x10, 0x3, 0x0)
sendmsg$nl_route(r0, &(0x7f0000000240)={0x0, 0x0, &(0x7f0000000040)={&(0x7f0000000940)=ANY=[@ANYBLOB="4000000010001fff000000000000f4f309000000", @ANYRES32=0x0, @ANYBLOB="81ff06ff00000000180012800e0001007769726567756172640000000381028008000a0061"], 0x40}}, 0x0)

program did not crash
single: failed to extract reproducer
single: executing 1 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$netlink-sendmsg$nl_route
detailed listing:
executing program 0:
r0 = socket$netlink(0x10, 0x3, 0x0)
sendmsg$nl_route(r0, &(0x7f0000000240)={0x0, 0x0, &(0x7f0000000040)={&(0x7f0000000940)=ANY=[@ANYBLOB="4000000010001fff000000000000f4f309000000", @ANYRES32=0x0, @ANYBLOB="81ff06ff00000000180012800e0001007769726567756172640000000381028008000a0061"], 0x40}}, 0x0)

program crashed: possible deadlock in lapbeth_device_event
single: successfully extracted reproducer
found reproducer with 2 syscalls
minimizing guilty program
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$netlink
detailed listing:
executing program 0:
socket$netlink(0x10, 0x3, 0x0)

program crashed: possible deadlock in lapbeth_device_event
extracting C reproducer
testing compiled C 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$netlink
program crashed: no output from test machine
a never seen crash title: no output from test machine, ignore
simplifying guilty program options
testing program (duration=6m0s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$netlink
detailed listing:
executing program 0:
socket$netlink(0x10, 0x3, 0x0)

program did not crash
testing program (duration=6m0s, {Threaded:true 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$netlink
detailed listing:
executing program 0:
socket$netlink(0x10, 0x3, 0x0)

program crashed: possible deadlock in lapbeth_device_event
extracting C reproducer
testing compiled C program (duration=6m0s, {Threaded:true 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$netlink
program crashed: no output from test machine
a never seen crash title: no output from test machine, ignore
reproducing took 31m24.08534594s
repro crashed as (corrupted=false):
============================================
WARNING: possible recursive locking detected
6.14.0-rc5-syzkaller-01152-g48c57a49c50a #0 Not tainted
--------------------------------------------
dhcpcd/5501 is trying to acquire lock:
ffff88807cd94d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
ffff88807cd94d28 (&dev->lock){+.+.}-{4:4}, at: netif_napi_add_weight include/linux/netdevice.h:2763 [inline]
ffff88807cd94d28 (&dev->lock){+.+.}-{4:4}, at: lapbeth_new_device drivers/net/wan/lapbether.c:415 [inline]
ffff88807cd94d28 (&dev->lock){+.+.}-{4:4}, at: lapbeth_device_event+0x766/0xa20 drivers/net/wan/lapbether.c:460

but task is already holding lock:
ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:40 [inline]
ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: dev_change_flags+0x120/0x270 net/core/dev_api.c:67

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: ffffffff8fed6908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8fed6908 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x34c/0x1d80 net/ipv4/devinet.c:1121
 #1: ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
 #1: ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:40 [inline]
 #1: ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: dev_change_flags+0x120/0x270 net/core/dev_api.c:67

stack backtrace:
CPU: 1 UID: 0 PID: 5501 Comm: dhcpcd Not tainted 6.14.0-rc5-syzkaller-01152-g48c57a49c50a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __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:2731 [inline]
 netif_napi_add_weight include/linux/netdevice.h:2763 [inline]
 lapbeth_new_device drivers/net/wan/lapbether.c:415 [inline]
 lapbeth_device_event+0x766/0xa20 drivers/net/wan/lapbether.c:460
 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
 __dev_notify_flags+0x207/0x400
 netif_change_flags+0xf0/0x1a0 net/core/dev.c:9443
 dev_change_flags+0x146/0x270 net/core/dev_api.c:68
 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: 0033:0x7fa98c9aed49
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:00007fff46788e68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa98c8e06c0 RCX: 00007fa98c9aed49
RDX: 00007fff46799058 RSI: 0000000000008914 RDI: 000000000000000f
RBP: 00007fff467a9218 R08: 00007fff46799018 R09: 00007fff46798fc8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff46799058 R14: 0000000000000028 R15: 0000000000008914
 </TASK>

final repro crashed as (corrupted=false):
============================================
WARNING: possible recursive locking detected
6.14.0-rc5-syzkaller-01152-g48c57a49c50a #0 Not tainted
--------------------------------------------
dhcpcd/5501 is trying to acquire lock:
ffff88807cd94d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
ffff88807cd94d28 (&dev->lock){+.+.}-{4:4}, at: netif_napi_add_weight include/linux/netdevice.h:2763 [inline]
ffff88807cd94d28 (&dev->lock){+.+.}-{4:4}, at: lapbeth_new_device drivers/net/wan/lapbether.c:415 [inline]
ffff88807cd94d28 (&dev->lock){+.+.}-{4:4}, at: lapbeth_device_event+0x766/0xa20 drivers/net/wan/lapbether.c:460

but task is already holding lock:
ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:40 [inline]
ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: dev_change_flags+0x120/0x270 net/core/dev_api.c:67

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: ffffffff8fed6908 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8fed6908 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x34c/0x1d80 net/ipv4/devinet.c:1121
 #1: ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2731 [inline]
 #1: ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:40 [inline]
 #1: ffff888034fd4d28 (&dev->lock){+.+.}-{4:4}, at: dev_change_flags+0x120/0x270 net/core/dev_api.c:67

stack backtrace:
CPU: 1 UID: 0 PID: 5501 Comm: dhcpcd Not tainted 6.14.0-rc5-syzkaller-01152-g48c57a49c50a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __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:2731 [inline]
 netif_napi_add_weight include/linux/netdevice.h:2763 [inline]
 lapbeth_new_device drivers/net/wan/lapbether.c:415 [inline]
 lapbeth_device_event+0x766/0xa20 drivers/net/wan/lapbether.c:460
 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
 __dev_notify_flags+0x207/0x400
 netif_change_flags+0xf0/0x1a0 net/core/dev.c:9443
 dev_change_flags+0x146/0x270 net/core/dev_api.c:68
 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: 0033:0x7fa98c9aed49
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:00007fff46788e68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa98c8e06c0 RCX: 00007fa98c9aed49
RDX: 00007fff46799058 RSI: 0000000000008914 RDI: 000000000000000f
RBP: 00007fff467a9218 R08: 00007fff46799018 R09: 00007fff46798fc8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff46799058 R14: 0000000000000028 R15: 0000000000008914
 </TASK>