================================================================== BUG: KASAN: slab-use-after-free in l2cap_sock_ready_cb+0xe3/0x180 net/bluetooth/l2cap_sock.c:1769 Read of size 8 at addr ffff88803e740200 by task kworker/u9:1/4932 CPU: 0 UID: 0 PID: 4932 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 05/09/2026 Workqueue: hci3 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:1769 l2cap_le_start+0x25b/0x1960 net/bluetooth/l2cap_core.c:1392 l2cap_conn_ready net/bluetooth/l2cap_core.c:1645 [inline] l2cap_connect_cfm+0x8d5/0x1560 net/bluetooth/l2cap_core.c:7498 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2136 le_conn_complete_evt+0x1134/0x16b0 net/bluetooth/hci_event.c:5869 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5895 hci_event_func net/bluetooth/hci_event.c:7797 [inline] hci_event_packet+0x659/0xef0 net/bluetooth/hci_event.c:7851 hci_rx_work+0x3ee/0x1040 net/bluetooth/hci_core.c:4039 process_one_work+0x98b/0x1630 kernel/workqueue.c:3326 process_scheduled_works kernel/workqueue.c:3409 [inline] worker_thread+0xb49/0x1140 kernel/workqueue.c:3490 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 8639: 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:5357 [inline] __kmalloc_noprof+0x420/0x7e0 mm/slub.c:5382 _kmalloc_noprof include/linux/slab.h:973 [inline] sk_prot_alloc+0xe7/0x210 net/core/sock.c:2252 sk_alloc+0x3a/0x390 net/core/sock.c:2308 bt_sock_alloc+0x3b/0x340 net/bluetooth/af_bluetooth.c:148 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1983 [inline] l2cap_sock_create+0x147/0x330 net/bluetooth/l2cap_sock.c:2025 bt_sock_create+0x163/0x240 net/bluetooth/af_bluetooth.c:132 __sock_create+0x4e3/0x960 net/socket.c:1666 sock_create net/socket.c:1724 [inline] __sys_socket_create net/socket.c:1761 [inline] __sys_socket+0xd9/0x330 net/socket.c:1808 __do_sys_socket net/socket.c:1822 [inline] __se_sys_socket net/socket.c:1820 [inline] __x64_sys_socket+0x7a/0x90 net/socket.c:1820 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 8639: 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:2699 [inline] slab_free mm/slub.c:6400 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6715 sk_prot_free net/core/sock.c:2291 [inline] __sk_destruct+0x74b/0x9d0 net/core/sock.c:2391 l2cap_sock_release+0x1c1/0x270 net/bluetooth/l2cap_sock.c:1478 __sock_release+0xb9/0x250 net/socket.c:714 sock_close+0x1c/0x30 net/socket.c:1516 __fput+0x461/0xa70 fs/file_table.c:512 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:70 [inline] exit_to_user_mode_loop+0x1fa/0x710 kernel/entry/common.c:101 __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 ffff88803e740000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 512 bytes inside of freed 4096-byte region [ffff88803e740000, ffff88803e741000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3e740 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 ffff88813fe31140 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813fe31140 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 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4983, tgid 4983 (udevd), ts 26506400879, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x265c/0x26e0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3288 [inline] allocate_slab+0x76/0x5d0 mm/slub.c:3406 new_slab mm/slub.c:3452 [inline] refill_objects+0x2d9/0x350 mm/slub.c:7333 refill_sheaf mm/slub.c:2826 [inline] __pcs_replace_empty_main+0x331/0x690 mm/slub.c:4698 alloc_from_pcs mm/slub.c:4796 [inline] slab_alloc_node mm/slub.c:4929 [inline] __do_kmalloc_node mm/slub.c:5356 [inline] __kmalloc_noprof+0x56d/0x7e0 mm/slub.c:5382 _kmalloc_noprof include/linux/slab.h:973 [inline] tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x229/0x470 security/tomoyo/file.c:776 security_file_open+0xa9/0x240 security/security.c:2739 do_dentry_open+0x4c0/0x13e0 fs/open.c:924 vfs_open+0x3b/0x350 fs/open.c:1052 do_open fs/namei.c:4700 [inline] path_openat+0x2e24/0x37e0 fs/namei.c:4859 do_file_open+0x23e/0x4a0 fs/namei.c:4888 do_sys_openat2+0x115/0x200 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1385 page_owner free stack trace missing Memory state around the buggy address: ffff88803e740100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803e740180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88803e740200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803e740280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803e740300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================