================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline] BUG: KASAN: slab-use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline] BUG: KASAN: slab-use-after-free in __refcount_add include/linux/refcount.h:283 [inline] BUG: KASAN: slab-use-after-free in __refcount_inc include/linux/refcount.h:366 [inline] BUG: KASAN: slab-use-after-free in refcount_inc include/linux/refcount.h:383 [inline] BUG: KASAN: slab-use-after-free in sock_hold include/net/sock.h:839 [inline] BUG: KASAN: slab-use-after-free in bt_accept_dequeue+0x6bd/0x920 net/bluetooth/af_bluetooth.c:351 Write of size 4 at addr ffff88807bc66080 by task syz.5.6532/2495 CPU: 1 UID: 0 PID: 2495 Comm: syz.5.6532 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:186 [inline] kasan_check_range+0x10f/0x1e0 mm/kasan/generic.c:200 instrument_atomic_read_write include/linux/instrumented.h:112 [inline] atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline] __refcount_add include/linux/refcount.h:283 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] sock_hold include/net/sock.h:839 [inline] bt_accept_dequeue+0x6bd/0x920 net/bluetooth/af_bluetooth.c:351 l2cap_sock_cleanup_listen+0x47/0x4d0 net/bluetooth/l2cap_sock.c:1507 l2cap_sock_release+0x69/0x280 net/bluetooth/l2cap_sock.c:1456 __sock_release+0xb3/0x260 net/socket.c:710 sock_close+0x1c/0x30 net/socket.c:1503 __fput+0x3ff/0xb50 fs/file_table.c:512 task_work_run+0x150/0x240 kernel/task_work.c:233 get_signal+0x1bd/0x21e0 kernel/signal.c:2810 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x6f0 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+0x666/0x870 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff8b0d9ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ff8b1bc0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000120 RAX: fffffffffffffe00 RBX: 00007ff8b1015fa0 RCX: 00007ff8b0d9ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007ff8b0e32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff8b1016038 R14: 00007ff8b1015fa0 R15: 00007ffe47787878 Allocated by task 5666: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5296 [inline] __kmalloc_noprof+0x301/0x850 mm/slub.c:5308 kmalloc_noprof include/linux/slab.h:954 [inline] sk_prot_alloc+0x10b/0x2a0 net/core/sock.c:2252 sk_alloc+0x36/0xe80 net/core/sock.c:2308 bt_sock_alloc+0x3b/0x3c0 net/bluetooth/af_bluetooth.c:151 l2cap_sock_alloc.constprop.0+0x33/0x1e0 net/bluetooth/l2cap_sock.c:1973 l2cap_sock_new_connection_cb+0x10f/0x260 net/bluetooth/l2cap_sock.c:1552 l2cap_connect_cfm+0x4e2/0xf80 net/bluetooth/l2cap_core.c:7473 hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline] hci_remote_features_evt+0x4f4/0x9b0 net/bluetooth/hci_event.c:3760 hci_event_func net/bluetooth/hci_event.c:7796 [inline] hci_event_packet+0x8e9/0xcd0 net/bluetooth/hci_event.c:7847 hci_rx_work+0x451/0xfc0 net/bluetooth/hci_core.c:4040 process_one_work+0xa23/0x1940 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 2495: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6251 [inline] kfree+0x22b/0x6c0 mm/slub.c:6566 sk_prot_free net/core/sock.c:2291 [inline] __sk_destruct+0x88c/0xab0 net/core/sock.c:2391 sk_destruct+0xc8/0xf0 net/core/sock.c:2419 __sk_free+0xf4/0x3e0 net/core/sock.c:2430 sk_free+0x61/0x90 net/core/sock.c:2441 sock_put include/net/sock.h:2011 [inline] bt_accept_unlink+0x22a/0x370 net/bluetooth/af_bluetooth.c:270 bt_accept_dequeue+0x791/0x920 net/bluetooth/af_bluetooth.c:339 l2cap_sock_cleanup_listen+0x47/0x4d0 net/bluetooth/l2cap_sock.c:1507 l2cap_sock_release+0x69/0x280 net/bluetooth/l2cap_sock.c:1456 __sock_release+0xb3/0x260 net/socket.c:710 sock_close+0x1c/0x30 net/socket.c:1503 __fput+0x3ff/0xb50 fs/file_table.c:512 task_work_run+0x150/0x240 kernel/task_work.c:233 get_signal+0x1bd/0x21e0 kernel/signal.c:2810 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x6f0 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+0x666/0x870 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88807bc66000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 128 bytes inside of freed 2048-byte region [ffff88807bc66000, ffff88807bc66800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807bc60000 pfn:0x7bc60 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88813fe34000 ffffea0001eec210 ffffea000203d610 raw: ffff88807bc60000 0000000800080006 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88813fe34000 ffffea0001eec210 ffffea000203d610 head: ffff88807bc60000 0000000800080006 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 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 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5661, tgid 5661 (syz-executor), ts 402625100719, free_ts 402555380071 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1853 prep_new_page mm/page_alloc.c:1861 [inline] get_page_from_freelist+0x11a6/0x3410 mm/page_alloc.c:3941 __alloc_frozen_pages_noprof+0x27c/0x2b60 mm/page_alloc.c:5221 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab mm/slub.c:3467 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3525 refill_objects+0xe3/0x430 mm/slub.c:7272 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x375/0x650 mm/slub.c:4652 alloc_from_pcs mm/slub.c:4750 [inline] slab_alloc_node mm/slub.c:4884 [inline] __do_kmalloc_node mm/slub.c:5295 [inline] __kmalloc_node_track_caller_noprof+0x694/0x850 mm/slub.c:5408 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:635 pskb_expand_head+0x249/0x10e0 net/core/skbuff.c:2303 netlink_trim+0x22d/0x2f0 net/netlink/af_netlink.c:1299 netlink_broadcast_filtered+0x6d/0xf20 net/netlink/af_netlink.c:1517 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xb1/0x290 net/netlink/af_netlink.c:2598 rtnl_notify net/core/rtnetlink.c:964 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:4474 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4490 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4477 [inline] rtnetlink_event+0x1b3/0x1f0 net/core/rtnetlink.c:7057 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2249 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] netif_change_name+0x4d9/0x830 net/core/dev.c:1509 page last free pid 5661 tgid 5661 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1397 [inline] __free_frozen_pages+0x794/0x10a0 mm/page_alloc.c:2938 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5296 [inline] __kmalloc_node_track_caller_noprof+0x304/0x850 mm/slub.c:5408 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:635 __alloc_skb+0x185/0x710 net/core/skbuff.c:713 alloc_skb include/linux/skbuff.h:1385 [inline] nlmsg_new include/net/netlink.h:1055 [inline] ctrl_build_family_msg+0x36/0xa0 net/netlink/genetlink.c:1387 ctrl_getfamily+0x361/0x550 net/netlink/genetlink.c:1467 genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2555 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1899 sock_sendmsg_nosec net/socket.c:775 [inline] __sock_sendmsg net/socket.c:790 [inline] __sys_sendto+0x468/0x4b0 net/socket.c:2254 Memory state around the buggy address: ffff88807bc65f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807bc66000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807bc66080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807bc66100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807bc66180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================