================================================================== 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_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline] BUG: KASAN: slab-use-after-free in hci_conn_drop+0x34/0x2a0 include/net/bluetooth/hci_core.h:1690 Write of size 4 at addr ffff88807da6c010 by task kworker/u9:0/11121 CPU: 1 UID: 0 PID: 11121 Comm: kworker/u9:0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Workqueue: hci4 hci_cmd_sync_work Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200 instrument_atomic_read_write include/linux/instrumented.h:112 [inline] atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline] hci_conn_drop+0x34/0x2a0 include/net/bluetooth/hci_core.h:1690 hci_cmd_sync_work+0x262/0x400 net/bluetooth/hci_sync.c:334 process_one_work+0x949/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0xb46/0x1140 kernel/workqueue.c:3443 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 5839: 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] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5290 kmalloc_noprof include/linux/slab.h:962 [inline] kzalloc_noprof include/linux/slab.h:1204 [inline] __hci_conn_add+0x3c4/0x1e00 net/bluetooth/hci_conn.c:963 le_conn_complete_evt+0x706/0x1430 net/bluetooth/hci_event.c:5740 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5873 hci_event_func net/bluetooth/hci_event.c:7781 [inline] hci_event_packet+0x7af/0x12c0 net/bluetooth/hci_event.c:7838 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4077 process_one_work+0x949/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0xb46/0x1140 kernel/workqueue.c:3443 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 5839: 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:2667 [inline] slab_free mm/slub.c:6075 [inline] kfree+0x1c1/0x610 mm/slub.c:6388 device_release+0x9e/0x1d0 drivers/base/core.c:-1 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x228/0x560 lib/kobject.c:737 hci_conn_cleanup net/bluetooth/hci_conn.c:173 [inline] hci_conn_del+0xc36/0x1230 net/bluetooth/hci_conn.c:1240 hci_disconn_complete_evt+0x64e/0x950 net/bluetooth/hci_event.c:3476 hci_event_func net/bluetooth/hci_event.c:7784 [inline] hci_event_packet+0x805/0x12c0 net/bluetooth/hci_event.c:7838 hci_rx_work+0x3ee/0x1030 net/bluetooth/hci_core.c:4077 process_one_work+0x949/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0xb46/0x1140 kernel/workqueue.c:3443 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff88807da6c000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 16 bytes inside of freed 8192-byte region [ffff88807da6c000, ffff88807da6e000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7da68 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813ff27280 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813ff27280 dead000000000100 dead000000000122 head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0001f69a01 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 0x528c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP), pid 5833, tgid 5833 (syz-executor), ts 89545426231, free_ts 87354471900 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1883 prep_new_page mm/page_alloc.c:1891 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3956 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5244 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2485 alloc_slab_page mm/slub.c:3233 [inline] allocate_slab+0x87/0x660 mm/slub.c:3408 new_slab mm/slub.c:3466 [inline] ___slab_alloc+0x150/0x6a0 mm/slub.c:4327 __slab_alloc_node mm/slub.c:4393 [inline] slab_alloc_node mm/slub.c:4769 [inline] __do_kmalloc_node mm/slub.c:5169 [inline] __kvmalloc_node_noprof+0x34d/0x8a0 mm/slub.c:6657 kvmalloc_array_node_noprof include/linux/slab.h:1232 [inline] __ptr_ring_init_queue_alloc_noprof include/linux/ptr_ring.h:481 [inline] ptr_ring_init_noprof include/linux/ptr_ring.h:499 [inline] skb_array_init_noprof include/linux/skb_array.h:182 [inline] pfifo_fast_init+0x372/0x6c0 net/sched/sch_generic.c:870 qdisc_create_dflt+0x13b/0x4c0 net/sched/sch_generic.c:1015 attach_one_default_qdisc net/sched/sch_generic.c:1174 [inline] netdev_for_each_tx_queue include/linux/netdevice.h:2685 [inline] attach_default_qdiscs net/sched/sch_generic.c:1192 [inline] dev_activate+0x378/0x1150 net/sched/sch_generic.c:1251 __dev_open+0x67a/0x830 net/core/dev.c:1704 __dev_change_flags+0x1f7/0x690 net/core/dev.c:9749 netif_change_flags+0x88/0x1a0 net/core/dev.c:9812 do_setlink+0xf82/0x4590 net/core/rtnetlink.c:3158 rtnl_changelink net/core/rtnetlink.c:3776 [inline] __rtnl_newlink net/core/rtnetlink.c:3935 [inline] rtnl_newlink+0x15a9/0x1be0 net/core/rtnetlink.c:4072 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958 page last free pid 5821 tgid 5821 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1432 [inline] __free_frozen_pages+0xc01/0xd80 mm/page_alloc.c:2972 __folio_put+0x414/0x4f0 mm/swap.c:112 put_netmem net/core/skbuff.c:7451 [inline] skb_page_unref include/linux/skbuff_ref.h:43 [inline] __skb_frag_unref include/linux/skbuff_ref.h:56 [inline] skb_release_data+0x4df/0x8e0 net/core/skbuff.c:1121 skb_release_all net/core/skbuff.c:1202 [inline] __kfree_skb+0x5d/0x210 net/core/skbuff.c:1216 tcp_clean_rtx_queue net/ipv4/tcp_input.c:3648 [inline] tcp_ack+0x26ed/0x7890 net/ipv4/tcp_input.c:4273 tcp_rcv_established+0xbeb/0x25b0 net/ipv4/tcp_input.c:6617 tcp_v4_do_rcv+0xa90/0x1430 net/ipv4/tcp_ipv4.c:1881 sk_backlog_rcv include/net/sock.h:1177 [inline] __release_sock+0x265/0x3a0 net/core/sock.c:3213 __sk_flush_backlog+0x36/0xc0 net/core/sock.c:3236 sk_flush_backlog include/net/sock.h:1240 [inline] tcp_sendmsg_locked+0x416e/0x5320 net/ipv4/tcp.c:1231 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1430 sock_sendmsg_nosec+0x128/0x1d0 net/socket.c:737 __sock_sendmsg net/socket.c:752 [inline] sock_write_iter+0x302/0x410 net/socket.c:1210 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61d/0xb90 fs/read_write.c:688 ksys_write+0x150/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 Memory state around the buggy address: ffff88807da6bf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807da6bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88807da6c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807da6c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807da6c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================