================================================================== BUG: KASAN: slab-use-after-free in l2cap_sock_ready_cb+0xe3/0x180 net/bluetooth/l2cap_sock.c:1772 Read of size 8 at addr ffff888033f4c200 by task kworker/u9:1/4928 CPU: 0 UID: 0 PID: 4928 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: hci1 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_sock_ready_cb+0xe3/0x180 net/bluetooth/l2cap_sock.c:1772 l2cap_le_start+0x25b/0x1960 net/bluetooth/l2cap_core.c:1393 l2cap_conn_ready net/bluetooth/l2cap_core.c:1646 [inline] l2cap_connect_cfm+0x8d5/0x1560 net/bluetooth/l2cap_core.c:7421 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+0x98b/0x1630 kernel/workqueue.c:3318 process_scheduled_works kernel/workqueue.c:3401 [inline] worker_thread+0xb49/0x1140 kernel/workqueue.c:3482 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 17291: 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] __do_kmalloc_node mm/slub.c:5309 [inline] __kmalloc_noprof+0x3e7/0x7b0 mm/slub.c:5322 _kmalloc_noprof include/linux/slab.h:971 [inline] sk_prot_alloc+0xe7/0x210 net/core/sock.c:2247 sk_alloc+0x3a/0x390 net/core/sock.c:2303 bt_sock_alloc+0x3b/0x340 net/bluetooth/af_bluetooth.c:151 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1986 [inline] l2cap_sock_create+0x147/0x330 net/bluetooth/l2cap_sock.c:2028 bt_sock_create+0x163/0x240 net/bluetooth/af_bluetooth.c:135 __sock_create+0x4e3/0x960 net/socket.c:1679 sock_create net/socket.c:1737 [inline] __sys_socket_create net/socket.c:1774 [inline] __sys_socket+0xd9/0x330 net/socket.c:1821 __do_sys_socket net/socket.c:1835 [inline] __se_sys_socket net/socket.c:1833 [inline] __x64_sys_socket+0x7a/0x90 net/socket.c:1833 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 17291: 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:6284 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6599 sk_prot_free net/core/sock.c:2286 [inline] __sk_destruct+0x74b/0x9d0 net/core/sock.c:2386 l2cap_sock_release+0x1c1/0x270 net/bluetooth/l2cap_sock.c:1481 __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 get_signal+0x11eb/0x1330 kernel/signal.c:2810 arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0xa9/0x680 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888033f4c000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 512 bytes inside of freed 4096-byte region [ffff888033f4c000, ffff888033f4d000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x33f48 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 ffff88813fe24140 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813fe24140 dead000000000100 dead000000000122 head: 0000000000000000 0000000800040004 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 1, tgid 1 (swapper/0), ts 22421790114, free_ts 22416850948 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1866 prep_new_page mm/page_alloc.c:1874 [inline] get_page_from_freelist+0x265c/0x26e0 mm/page_alloc.c:3953 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5307 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:7216 refill_sheaf mm/slub.c:2827 [inline] __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4665 alloc_from_pcs mm/slub.c:4763 [inline] slab_alloc_node mm/slub.c:4897 [inline] __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5420 _kmalloc_noprof include/linux/slab.h:967 [inline] _kzalloc_noprof include/linux/slab.h:1284 [inline] kobject_uevent_env+0x28f/0x9e0 lib/kobject_uevent.c:543 kernel_add_sysfs_param+0xb1/0xe0 kernel/params.c:801 param_sysfs_builtin+0x199/0x250 kernel/params.c:836 param_sysfs_builtin_init+0x23/0x30 kernel/params.c:972 do_one_initcall+0x250/0x870 init/main.c:1347 do_initcall_level+0x104/0x190 init/main.c:1409 do_initcalls+0x59/0xa0 init/main.c:1425 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1658 kernel_init+0x1d/0x1d0 init/main.c:1548 page last free pid 2081 tgid 2081 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1413 [inline] free_pages_prepare+0x947/0xa40 mm/page_alloc.c:1458 __free_contig_range_common+0x174/0x340 mm/page_alloc.c:6898 __free_contig_range mm/page_alloc.c:6943 [inline] free_pages_bulk+0x48/0x120 mm/page_alloc.c:5260 vm_area_free_pages mm/vmalloc.c:3439 [inline] vfree+0x26f/0x500 mm/vmalloc.c:3488 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3392 process_one_work+0x98b/0x1630 kernel/workqueue.c:3318 process_scheduled_works kernel/workqueue.c:3401 [inline] worker_thread+0xb49/0x1140 kernel/workqueue.c:3482 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 Memory state around the buggy address: ffff888033f4c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888033f4c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888033f4c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888033f4c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888033f4c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================