================================================================== BUG: KASAN: slab-use-after-free in rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56 Read of size 1 at addr ffff8880277607e8 by task syz.2.3496/13820 CPU: 1 UID: 0 PID: 13820 Comm: syz.2.3496 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 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 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574 kasan_check_byte include/linux/kasan.h:402 [inline] lock_acquire+0x7d/0x350 kernel/locking/lockdep.c:5880 rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56 spin_lock_bh include/linux/spinlock_rt.h:90 [inline] bt_accept_unlink+0x7d/0x2f0 net/bluetooth/af_bluetooth.c:263 l2cap_sock_teardown_cb+0x17e/0x490 net/bluetooth/l2cap_sock.c:1711 l2cap_chan_del+0x98/0x600 net/bluetooth/l2cap_core.c:687 l2cap_conn_del+0x2f2/0x520 net/bluetooth/l2cap_core.c:1825 hci_disconn_cfm include/net/bluetooth/hci_core.h:2152 [inline] hci_conn_hash_flush+0x105/0x260 net/bluetooth/hci_conn.c:2733 hci_dev_close_sync+0x7fc/0x10a0 net/bluetooth/hci_sync.c:5381 hci_dev_do_close net/bluetooth/hci_core.c:502 [inline] hci_unregister_dev+0x232/0x5b0 net/bluetooth/hci_core.c:2681 vhci_release+0x170/0x1c0 drivers/bluetooth/hci_vhci.c:700 __fput+0x42a/0xa80 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x73a/0x2360 kernel/exit.c:1009 do_group_exit+0x22d/0x2f0 kernel/exit.c:1152 get_signal+0x121b/0x12c0 kernel/signal.c:3039 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x104/0x730 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:316 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f18e2e0e68e Code: Unable to access opcode bytes at 0x7f18e2e0e664. RSP: 002b:00007f18e10a5f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007f18e10a66c0 RCX: 00007f18e2e0e68e RDX: 00007f18e10a5fb0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f18e2ee3e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f18e30d6038 R14: 00007f18e30d5fa0 R15: 00007ffd1dedb7d8 Allocated by task 4963: 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:5339 [inline] __kmalloc_noprof+0x415/0x790 mm/slub.c:5364 _kmalloc_noprof include/linux/slab.h:973 [inline] tomoyo_realpath_from_path+0xef/0x640 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827 security_inode_getattr+0x121/0x2d0 security/security.c:1895 vfs_getattr fs/stat.c:259 [inline] vfs_fstat fs/stat.c:281 [inline] __do_sys_newfstat fs/stat.c:551 [inline] __se_sys_newfstat fs/stat.c:546 [inline] __x64_sys_newfstat+0x133/0x270 fs/stat.c:546 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 4963: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 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:2706 [inline] slab_free mm/slub.c:6374 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6689 tomoyo_realpath_from_path+0x605/0x640 security/tomoyo/realpath.c:286 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827 security_inode_getattr+0x121/0x2d0 security/security.c:1895 vfs_getattr fs/stat.c:259 [inline] vfs_fstat fs/stat.c:281 [inline] __do_sys_newfstat fs/stat.c:551 [inline] __se_sys_newfstat fs/stat.c:546 [inline] __x64_sys_newfstat+0x133/0x270 fs/stat.c:546 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 The buggy address belongs to the object at ffff888027760000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 2024 bytes inside of freed 4096-byte region [ffff888027760000, ffff888027761000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27760 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 ffff88813fe3a140 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813fe3a140 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 6613048892 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1862 prep_new_page mm/page_alloc.c:1870 [inline] get_page_from_freelist+0x264c/0x26c0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x222/0x5b0 mm/page_alloc.c:5385 alloc_slab_page mm/slub.c:3295 [inline] allocate_slab+0x7c/0x5e0 mm/slub.c:3410 new_slab mm/slub.c:3456 [inline] refill_objects+0x2d8/0x350 mm/slub.c:7307 refill_sheaf mm/slub.c:2833 [inline] __pcs_replace_empty_main+0x330/0x690 mm/slub.c:4699 alloc_from_pcs mm/slub.c:4775 [inline] slab_alloc_node mm/slub.c:4909 [inline] __kmalloc_cache_noprof+0x467/0x670 mm/slub.c:5482 _kmalloc_noprof include/linux/slab.h:969 [inline] _kzalloc_noprof include/linux/slab.h:1290 [inline] kobject_uevent_env+0x28c/0x9e0 lib/kobject_uevent.c:543 disk_uevent+0x297/0x470 block/genhd.c:355 add_disk_final block/genhd.c:423 [inline] add_disk_fwnode+0x387/0x4b0 block/genhd.c:610 add_disk include/linux/blkdev.h:798 [inline] brd_alloc+0x5ba/0x7c0 drivers/block/brd.c:340 brd_init+0xc1/0x120 drivers/block/brd.c:420 do_one_initcall+0x250/0x870 init/main.c:1357 do_initcall_level+0x10a/0x1a0 init/main.c:1419 do_initcalls+0x59/0xa0 init/main.c:1435 kernel_init_freeable+0x29d/0x3e0 init/main.c:1670 page_owner free stack trace missing Memory state around the buggy address: ffff888027760680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888027760700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888027760780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888027760800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888027760880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================