================================================================== BUG: KASAN: slab-use-after-free in __mutex_waiter_is_first kernel/locking/mutex.c:199 [inline] BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:694 [inline] BUG: KASAN: slab-use-after-free in __mutex_lock+0x812/0x1300 kernel/locking/mutex.c:776 Read of size 8 at addr ffff88803abfcae8 by task syz.4.13171/21925 CPU: 1 UID: 0 PID: 21925 Comm: syz.4.13171 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 __mutex_waiter_is_first kernel/locking/mutex.c:199 [inline] __mutex_lock_common kernel/locking/mutex.c:694 [inline] __mutex_lock+0x812/0x1300 kernel/locking/mutex.c:776 l2cap_unregister_user+0x36/0x170 net/bluetooth/l2cap_core.c:1740 hidp_connection_del+0xb0/0x170 net/bluetooth/hidp/core.c:1421 do_hidp_sock_ioctl net/bluetooth/hidp/sock.c:97 [inline] hidp_sock_ioctl+0x3ab/0x650 net/bluetooth/hidp/sock.c:128 sock_do_ioctl+0x101/0x320 net/socket.c:1254 sock_ioctl+0x5c6/0x7f0 net/socket.c:1375 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f654979c799 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:00007f654a71d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f6549a16090 RCX: 00007f654979c799 RDX: 0000200000000000 RSI: 00000000400448c9 RDI: 0000000000000006 RBP: 00007f6549832c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6549a16128 R14: 00007f6549a16090 R15: 00007fffc91fedd8 Allocated by task 12197: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5380 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] l2cap_conn_add+0xaa/0x960 net/bluetooth/l2cap_core.c:6996 l2cap_connect_cfm+0x142/0x1560 net/bluetooth/l2cap_core.c:7373 hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline] hci_remote_features_evt+0x5b9/0x950 net/bluetooth/hci_event.c:3754 hci_event_func net/bluetooth/hci_event.c:7784 [inline] hci_event_packet+0x805/0x12c0 net/bluetooth/hci_event.c:7838 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4077 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 21839: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kfree+0x1c1/0x630 mm/slub.c:6483 hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline] hci_conn_hash_flush+0x10d/0x260 net/bluetooth/hci_conn.c:2644 hci_dev_close_sync+0x821/0x10e0 net/bluetooth/hci_sync.c:5358 hci_dev_do_close+0x30/0xc0 net/bluetooth/hci_core.c:502 hci_rfkill_set_block+0x1f4/0x290 net/bluetooth/hci_core.c:930 rfkill_set_block+0x1d2/0x440 net/rfkill/core.c:346 rfkill_fop_write+0x461/0x5a0 net/rfkill/core.c:1301 vfs_write+0x29a/0xb90 fs/read_write.c:686 ksys_write+0x150/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 insert_work+0x3d/0x330 kernel/workqueue.c:2199 __queue_work+0xd03/0x1020 kernel/workqueue.c:2354 call_timer_fn+0x192/0x640 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1794 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x67e/0x8b0 kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404 handle_softirqs+0x22a/0x870 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 Second to last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 insert_work+0x3d/0x330 kernel/workqueue.c:2199 __queue_work+0xbe1/0x1020 kernel/workqueue.c:2358 queue_work_on+0x106/0x1d0 kernel/workqueue.c:2405 queue_work include/linux/workqueue.h:669 [inline] l2cap_conn_ready net/bluetooth/l2cap_core.c:1660 [inline] l2cap_connect_cfm+0x10f5/0x1560 net/bluetooth/l2cap_core.c:7414 hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline] hci_remote_features_evt+0x5b9/0x950 net/bluetooth/hci_event.c:3754 hci_event_func net/bluetooth/hci_event.c:7784 [inline] hci_event_packet+0x805/0x12c0 net/bluetooth/hci_event.c:7838 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4077 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff88803abfc800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 744 bytes inside of freed 1024-byte region [ffff88803abfc800, ffff88803abfcc00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803abfd800 pfn:0x3abf8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88813fea5dc0 ffffea0000c6c410 ffffea000156aa10 raw: ffff88803abfd800 0000000800100007 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88813fea5dc0 ffffea0000c6c410 ffffea000156aa10 head: ffff88803abfd800 0000000800100007 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000eafe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 17861, tgid 17861 (syz-executor), ts 1187048789767, free_ts 969392612539 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3292 [inline] allocate_slab+0x77/0x660 mm/slub.c:3481 new_slab mm/slub.c:3539 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7175 refill_sheaf mm/slub.c:2812 [inline] __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615 alloc_from_pcs mm/slub.c:4717 [inline] slab_alloc_node mm/slub.c:4851 [inline] __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5375 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] batadv_hardif_add_interface net/batman-adv/hard-interface.c:874 [inline] batadv_hard_if_event+0xe7a/0x1700 net/batman-adv/hard-interface.c:958 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] register_netdevice+0x173a/0x1cf0 net/core/dev.c:11474 veth_newlink+0x4a4/0xb70 drivers/net/veth.c:1860 rtnl_newlink_create+0x329/0xb70 net/core/rtnetlink.c:3862 __rtnl_newlink net/core/rtnetlink.c:3979 [inline] rtnl_newlink+0x1666/0x1be0 net/core/rtnetlink.c:4094 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6980 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 page last free pid 15321 tgid 15321 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978 vfree+0x25a/0x400 mm/vmalloc.c:3479 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3398 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88803abfc980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803abfca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88803abfca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803abfcb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803abfcb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================