================================================================== BUG: KASAN: slab-use-after-free in __list_del_entry_valid_or_report+0x92/0x190 lib/list_debug.c:62 Read of size 8 at addr ffff88805fa97780 by task syz.2.328/6739 CPU: 0 UID: 0 PID: 6739 Comm: syz.2.328 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 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 __list_del_entry_valid_or_report+0x92/0x190 lib/list_debug.c:62 __list_del_entry_valid include/linux/list.h:132 [inline] __list_del_entry include/linux/list.h:223 [inline] list_del_init include/linux/list.h:295 [inline] bt_accept_unlink+0x39/0x260 net/bluetooth/af_bluetooth.c:259 l2cap_sock_teardown_cb+0x17e/0x490 net/bluetooth/l2cap_sock.c:1643 l2cap_chan_del+0xb5/0x610 net/bluetooth/l2cap_core.c:656 l2cap_conn_del+0x33d/0x570 net/bluetooth/l2cap_core.c:1802 hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline] hci_conn_hash_flush+0x10d/0x260 net/bluetooth/hci_conn.c:2734 hci_dev_close_sync+0x821/0x10e0 net/bluetooth/hci_sync.c:5368 hci_dev_do_close net/bluetooth/hci_core.c:502 [inline] hci_unregister_dev+0x21a/0x5a0 net/bluetooth/hci_core.c:2716 vhci_release+0x155/0x1b0 drivers/bluetooth/hci_vhci.c:690 __fput+0x461/0xa70 fs/file_table.c:510 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x70f/0x22c0 kernel/exit.c:975 do_group_exit+0x21b/0x2d0 kernel/exit.c:1117 get_signal+0x1284/0x1330 kernel/signal.c:3037 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 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:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8fb055d60e Code: Unable to access opcode bytes at 0x7f8fb055d5e4. RSP: 002b:00007f8fae7f5f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007f8fae7f66c0 RCX: 00007f8fb055d60e RDX: 00007f8fae7f5fb0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f8fb0632d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8fb0816038 R14: 00007f8fb0815fa0 R15: 00007ffc2df21568 Allocated by task 8554: 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:5303 [inline] __kmalloc_noprof+0x3e7/0x7b0 mm/slub.c:5315 kmalloc_noprof include/linux/slab.h:954 [inline] sk_prot_alloc+0xe7/0x210 net/core/sock.c:2247 sk_alloc+0x3a/0x390 net/core/sock.c:2303 bt_sock_alloc+0x3b/0x310 net/bluetooth/af_bluetooth.c:151 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1934 [inline] l2cap_sock_create+0x147/0x330 net/bluetooth/l2cap_sock.c:1976 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+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 8553: 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:6258 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6573 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:1463 __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/0x480 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:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88805fa97000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1920 bytes inside of freed 2048-byte region [ffff88805fa97000, ffff88805fa97800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5fa90 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 ffff88813fe16000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813fe16000 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 4964, tgid 4964 (klogd), ts 104353202257, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1853 prep_new_page mm/page_alloc.c:1861 [inline] get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3941 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5249 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:7263 refill_sheaf mm/slub.c:2827 [inline] __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4659 alloc_from_pcs mm/slub.c:4757 [inline] slab_alloc_node mm/slub.c:4891 [inline] __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5422 kmalloc_noprof include/linux/slab.h:950 [inline] syslog_print+0x103/0x610 kernel/printk/printk.c:1585 do_syslog+0x583/0x7d0 kernel/printk/printk.c:1763 __do_sys_syslog kernel/printk/printk.c:1855 [inline] __se_sys_syslog kernel/printk/printk.c:1853 [inline] __x64_sys_syslog+0x7c/0x90 kernel/printk/printk.c:1853 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 page_owner free stack trace missing Memory state around the buggy address: ffff88805fa97680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805fa97700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88805fa97780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805fa97800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88805fa97880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================