ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 kobject: kobject_add_internal failed for hci2:201 with -EEXIST, don't try to register things with the same name in the same directory. Bluetooth: hci2: failed to register connection device ================================================================== BUG: KASAN: slab-use-after-free in l2cap_conn_ready net/bluetooth/l2cap_core.c:1639 [inline] BUG: KASAN: slab-use-after-free in l2cap_connect_cfm+0x902/0x1560 net/bluetooth/l2cap_core.c:7419 Read of size 8 at addr ffff888044447500 by task kworker/u9:1/18206 CPU: 1 UID: 0 PID: 18206 Comm: kworker/u9:1 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: hci2 hci_rx_work Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 l2cap_conn_ready net/bluetooth/l2cap_core.c:1639 [inline] l2cap_connect_cfm+0x902/0x1560 net/bluetooth/l2cap_core.c:7419 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2139 le_conn_complete_evt+0x1134/0x16b0 net/bluetooth/hci_event.c:5865 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5891 hci_event_func net/bluetooth/hci_event.c:7793 [inline] hci_event_packet+0x659/0xef0 net/bluetooth/hci_event.c:7847 hci_rx_work+0x3ee/0x1040 net/bluetooth/hci_core.c:4077 process_one_work+0xa31/0x1980 kernel/workqueue.c:3320 process_scheduled_works kernel/workqueue.c:3423 [inline] worker_thread+0xba8/0x11e0 kernel/workqueue.c:3509 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 18206: 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+0x3a6/0x690 mm/slub.c:5432 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] l2cap_chan_create+0x51/0x7a0 net/bluetooth/l2cap_core.c:445 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1943 [inline] l2cap_sock_new_connection_cb+0x191/0x2f0 net/bluetooth/l2cap_sock.c:1513 l2cap_connect_cfm+0x368/0x1560 net/bluetooth/l2cap_core.c:7402 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2139 le_conn_complete_evt+0x1134/0x16b0 net/bluetooth/hci_event.c:5865 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5891 hci_event_func net/bluetooth/hci_event.c:7793 [inline] hci_event_packet+0x659/0xef0 net/bluetooth/hci_event.c:7847 hci_rx_work+0x3ee/0x1040 net/bluetooth/hci_core.c:4077 process_one_work+0xa31/0x1980 kernel/workqueue.c:3320 process_scheduled_works kernel/workqueue.c:3423 [inline] worker_thread+0xba8/0x11e0 kernel/workqueue.c:3509 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 8725: 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:2700 [inline] slab_free mm/slub.c:6291 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6606 l2cap_sock_cleanup_listen+0xf0/0x440 net/bluetooth/l2cap_sock.c:1493 l2cap_sock_release+0x6e/0x270 net/bluetooth/l2cap_sock.c:1451 __sock_release+0xb9/0x250 net/socket.c:726 sock_close+0x1c/0x30 net/socket.c:1529 __fput+0x461/0xa70 fs/file_table.c:510 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x4d0 kernel/entry/common.c:98 The buggy address belongs to the object at ffff888044447000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1280 bytes inside of freed 2048-byte region [ffff888044447000, ffff888044447800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x44440 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000040 ffff88813fe17000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813fe17000 dead000000000100 dead000000000122 head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: 0000000000000000 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 26870, tgid 26870 (syz-executor), ts 1493568285865, free_ts 1493557350073 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1861 prep_new_page mm/page_alloc.c:1869 [inline] get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3949 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5292 alloc_slab_page mm/slub.c:3289 [inline] allocate_slab+0x74/0x5e0 mm/slub.c:3404 new_slab mm/slub.c:3447 [inline] refill_objects+0x33c/0x3d0 mm/slub.c:7319 refill_sheaf mm/slub.c:2827 [inline] __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4664 alloc_from_pcs mm/slub.c:4762 [inline] slab_alloc_node mm/slub.c:4896 [inline] __do_kmalloc_node mm/slub.c:5307 [inline] __kvmalloc_node_noprof+0x6f4/0x8e0 mm/slub.c:6873 kvmalloc_array_node_noprof include/linux/slab.h:1216 [inline] __ptr_ring_init_queue_alloc_noprof include/linux/ptr_ring.h:481 [inline] ptr_ring_init_noprof include/linux/ptr_ring.h:499 [inline] page_pool_init net/core/page_pool.c:262 [inline] page_pool_create_percpu+0x30d/0xc90 net/core/page_pool.c:352 nsim_create_page_pool drivers/net/netdevsim/netdev.c:429 [inline] nsim_init_napi drivers/net/netdevsim/netdev.c:452 [inline] nsim_open+0x3c4/0xa20 drivers/net/netdevsim/netdev.c:508 __dev_open+0x44d/0x830 net/core/dev.c:1702 __dev_change_flags+0x2fa/0x7e0 net/core/dev.c:9756 netif_change_flags+0x88/0x1a0 net/core/dev.c:9819 do_setlink+0xfa5/0x45a0 net/core/rtnetlink.c:3181 rtnl_changelink net/core/rtnetlink.c:3800 [inline] __rtnl_newlink net/core/rtnetlink.c:3973 [inline] rtnl_newlink+0x15ad/0x1bb0 net/core/rtnetlink.c:4110 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6996 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2551 page last free pid 27156 tgid 27156 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1405 [inline] __free_frozen_pages+0x1075/0x11b0 mm/page_alloc.c:2946 __slab_free+0x252/0x2a0 mm/slub.c:5653 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4582 [inline] slab_alloc_node mm/slub.c:4911 [inline] kmem_cache_alloc_lru_noprof+0x33c/0x680 mm/slub.c:4930 alloc_inode+0xb8/0x1b0 fs/inode.c:347 new_inode_pseudo include/linux/fs.h:3015 [inline] get_pipe_inode fs/pipe.c:888 [inline] create_pipe_files+0x51/0x7e0 fs/pipe.c:928 __do_pipe_flags+0x46/0x1f0 fs/pipe.c:990 do_pipe2+0xaa/0x190 fs/pipe.c:1038 __do_sys_pipe2 fs/pipe.c:1056 [inline] __se_sys_pipe2 fs/pipe.c:1054 [inline] __x64_sys_pipe2+0x5a/0x70 fs/pipe.c:1054 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888044447400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888044447480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888044447500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888044447580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888044447600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================