ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 kobject: kobject_add_internal failed for hci4:201 with -EEXIST, don't try to register things with the same name in the same directory. Bluetooth: hci4: failed to register connection device ================================================================== BUG: KASAN: slab-use-after-free in l2cap_sock_new_connection_cb+0x1f9/0x2e0 net/bluetooth/l2cap_sock.c:1500 Read of size 8 at addr ffff888036d8c7b0 by task kworker/u9:0/61 CPU: 1 UID: 0 PID: 61 Comm: kworker/u9:0 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: hci4 hci_rx_work Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 l2cap_sock_new_connection_cb+0x1f9/0x2e0 net/bluetooth/l2cap_sock.c:1500 l2cap_connect_cfm+0x367/0x10e0 net/bluetooth/l2cap_core.c:7288 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2131 le_conn_complete_evt+0xf65/0x1420 net/bluetooth/hci_event.c:5821 hci_le_conn_complete_evt+0x187/0x480 net/bluetooth/hci_event.c:5847 hci_event_func net/bluetooth/hci_event.c:7716 [inline] hci_event_packet+0x78f/0x1260 net/bluetooth/hci_event.c:7773 hci_rx_work+0x3ee/0x1060 net/bluetooth/hci_core.c:4076 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Allocated by task 61: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5657 [inline] __kmalloc_noprof+0x23e/0x7e0 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] sk_prot_alloc+0xe7/0x220 net/core/sock.c:2245 sk_alloc+0x3a/0x390 net/core/sock.c:2301 bt_sock_alloc+0x3b/0x310 net/bluetooth/af_bluetooth.c:151 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1897 [inline] l2cap_sock_new_connection_cb+0xe2/0x2e0 net/bluetooth/l2cap_sock.c:1485 l2cap_connect_cfm+0x367/0x10e0 net/bluetooth/l2cap_core.c:7288 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2131 le_conn_complete_evt+0xf65/0x1420 net/bluetooth/hci_event.c:5821 hci_le_conn_complete_evt+0x187/0x480 net/bluetooth/hci_event.c:5847 hci_event_func net/bluetooth/hci_event.c:7716 [inline] hci_event_packet+0x78f/0x1260 net/bluetooth/hci_event.c:7773 hci_rx_work+0x3ee/0x1060 net/bluetooth/hci_core.c:4076 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Freed by task 7316: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6670 [inline] kfree+0x1bd/0x900 mm/slub.c:6878 sk_prot_free net/core/sock.c:2284 [inline] __sk_destruct+0x626/0x880 net/core/sock.c:2384 l2cap_sock_cleanup_listen+0xe0/0x450 net/bluetooth/l2cap_sock.c:1465 l2cap_sock_release+0x6e/0x270 net/bluetooth/l2cap_sock.c:1426 __sock_release net/socket.c:662 [inline] sock_close+0xc3/0x240 net/socket.c:1455 __fput+0x45b/0xa80 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:233 get_signal+0x11c4/0x1310 kernel/signal.c:2807 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888036d8c000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1968 bytes inside of freed 2048-byte region [ffff888036d8c000, ffff888036d8c800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x36d88 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 ffff88813ff27000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122 head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 head: 0080000000000003 ffffea0000db6201 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 5157, tgid 5157 (klogd), ts 104304618814, free_ts 104089003224 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab+0x86/0x3b0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xb10/0x13e0 mm/slub.c:4656 __slab_alloc+0xc6/0x1f0 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __kmalloc_cache_noprof+0x101/0x6d0 mm/slub.c:5771 kmalloc_noprof include/linux/slab.h:957 [inline] syslog_print+0xd2/0x590 kernel/printk/printk.c:1583 do_syslog+0x544/0x760 kernel/printk/printk.c:1761 __do_sys_syslog kernel/printk/printk.c:1853 [inline] __se_sys_syslog kernel/printk/printk.c:1851 [inline] __x64_sys_syslog+0x7c/0x90 kernel/printk/printk.c:1851 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 5796 tgid 5796 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0xfe1/0x1170 mm/page_alloc.c:2943 discard_slab mm/slub.c:3346 [inline] __put_partials+0x149/0x170 mm/slub.c:3886 __slab_free+0x2af/0x330 mm/slub.c:5952 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:349 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] __kmalloc_cache_noprof+0x18d/0x6d0 mm/slub.c:5771 kmalloc_noprof include/linux/slab.h:957 [inline] __netdev_adjacent_dev_insert+0x158/0x940 net/core/dev.c:8678 __netdev_adjacent_dev_link_lists net/core/dev.c:8770 [inline] __netdev_adjacent_dev_link_neighbour net/core/dev.c:8799 [inline] __netdev_upper_dev_link+0x322/0x550 net/core/dev.c:8859 netdev_master_upper_dev_link+0xb0/0x100 net/core/dev.c:8934 hsr_portdev_setup net/hsr/hsr_slave.c:165 [inline] hsr_add_port+0x68b/0xa30 net/hsr/hsr_slave.c:213 hsr_dev_finalize+0x6d4/0xab0 net/hsr/hsr_device.c:792 hsr_newlink+0x8ad/0x9f0 net/hsr/hsr_netlink.c:128 rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3840 __rtnl_newlink net/core/rtnetlink.c:3957 [inline] rtnl_newlink+0x16e7/0x1c90 net/core/rtnetlink.c:4072 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958 Memory state around the buggy address: ffff888036d8c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888036d8c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888036d8c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888036d8c800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888036d8c880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================