CPU: 0 UID: 0 PID: 15543 Comm: syz.5.2049 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0x95/0xd0 lib/dump_stack.c:120 ================================================================== BUG: KCSAN: data-race in data_alloc / prb_reserve write to 0xffffffff86c74730 of 8 bytes by task 5299 on cpu 1: data_alloc+0x308/0x380 kernel/printk/printk_ringbuffer.c:1130 prb_reserve+0x8e3/0xaf0 kernel/printk/printk_ringbuffer.c:1727 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2504 __netdev_printk+0x310/0x370 net/core/dev.c:12972 netdev_info+0xa6/0xd0 net/core/dev.c:13019 team_port_del+0xb29/0xba0 drivers/net/team/team_core.c:1468 team_del_slave_on_unregister drivers/net/team/team_core.c:2131 [inline] team_device_event+0x12c/0x350 drivers/net/team/team_core.c:3192 notifier_call_chain kernel/notifier.c:85 [inline] raw_notifier_call_chain+0x72/0x1a0 kernel/notifier.c:453 call_netdevice_notifiers_info net/core/dev.c:2250 [inline] call_netdevice_notifiers_extack net/core/dev.c:2288 [inline] call_netdevice_notifiers net/core/dev.c:2302 [inline] unregister_netdevice_many_notify+0xe1a/0x1550 net/core/dev.c:12446 unregister_netdevice_many net/core/dev.c:12507 [inline] default_device_exit_batch+0x5d7/0x630 net/core/dev.c:13099 ops_exit_list net/core/net_namespace.c:205 [inline] ops_undo_list+0x2ca/0x420 net/core/net_namespace.c:252 cleanup_net+0x37c/0x5b0 net/core/net_namespace.c:702 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405 worker_thread+0x569/0x750 kernel/workqueue.c:3486 kthread+0x221/0x270 kernel/kthread.c:436 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 read to 0xffffffff86c74730 of 8 bytes by task 15543 on cpu 0: desc_read kernel/printk/printk_ringbuffer.c:496 [inline] desc_push_tail kernel/printk/printk_ringbuffer.c:792 [inline] desc_reserve kernel/printk/printk_ringbuffer.c:938 [inline] prb_reserve+0x21a/0xaf0 kernel/printk/printk_ringbuffer.c:1677 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2504 printk_stack_address arch/x86/kernel/dumpstack.c:70 [inline] __show_trace_log_lvl+0x460/0x560 arch/x86/kernel/dumpstack.c:282 __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0x95/0xd0 lib/dump_stack.c:120 dump_stack+0x15/0x1b lib/dump_stack.c:129 fail_dump lib/fault-inject.c:73 [inline] should_fail_ex+0x25e/0x270 lib/fault-inject.c:174 should_failslab+0x8c/0xb0 mm/failslab.c:46 slab_pre_alloc_hook mm/slub.c:4567 [inline] slab_alloc_node mm/slub.c:4925 [inline] kmem_cache_alloc_node_noprof+0x85/0x3d0 mm/slub.c:5017 __alloc_skb+0x2db/0x6f0 net/core/skbuff.c:704 alloc_skb include/linux/skbuff.h:1384 [inline] bt_skb_alloc include/net/bluetooth/bluetooth.h:517 [inline] create_monitor_ctrl_open+0x118/0x4a0 net/bluetooth/hci_sock.c:589 hci_sock_ioctl+0x2a9/0x7e0 net/bluetooth/hci_sock.c:1105 sock_do_ioctl+0x73/0x230 net/socket.c:1300 sock_ioctl+0x439/0x610 net/socket.c:1421 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583 x64_sys_call+0x1563/0x3020 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0xffffffffffff5a80 -> 0x0000000000093b28 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 15543 Comm: syz.5.2049 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 ================================================================== dump_stack+0x15/0x1b lib/dump_stack.c:129 fail_dump lib/fault-inject.c:73 [inline] should_fail_ex+0x25e/0x270 lib/fault-inject.c:174 should_failslab+0x8c/0xb0 mm/failslab.c:46 slab_pre_alloc_hook mm/slub.c:4567 [inline] slab_alloc_node mm/slub.c:4925 [inline] kmem_cache_alloc_node_noprof+0x85/0x3d0 mm/slub.c:5017 __alloc_skb+0x2db/0x6f0 net/core/skbuff.c:704 alloc_skb include/linux/skbuff.h:1384 [inline] bt_skb_alloc include/net/bluetooth/bluetooth.h:517 [inline] create_monitor_ctrl_open+0x118/0x4a0 net/bluetooth/hci_sock.c:589 hci_sock_ioctl+0x2a9/0x7e0 net/bluetooth/hci_sock.c:1105 sock_do_ioctl+0x73/0x230 net/socket.c:1300 sock_ioctl+0x439/0x610 net/socket.c:1421 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583 x64_sys_call+0x1563/0x3020 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fede214de99 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fede0ba7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fede23d5fa0 RCX: 00007fede214de99 RDX: 0000200000000240 RSI: 00000000400448e4 RDI: 0000000000000008 RBP: 00007fede0ba7090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fede23d6038 R14: 00007fede23d5fa0 R15: 00007ffcde4205e8