================================================================== BUG: KASAN: slab-use-after-free in l2cap_conn_ready net/bluetooth/l2cap_core.c:1623 [inline] BUG: KASAN: slab-use-after-free in l2cap_connect_cfm+0x6e4/0x1040 net/bluetooth/l2cap_core.c:7304 Read of size 8 at addr ffff8880288a9500 by task kworker/u9:2/5835 CPU: 0 UID: 0 PID: 5835 Comm: kworker/u9:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: hci1 hci_rx_work Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 l2cap_conn_ready net/bluetooth/l2cap_core.c:1623 [inline] l2cap_connect_cfm+0x6e4/0x1040 net/bluetooth/l2cap_core.c:7304 hci_connect_cfm+0x92/0x140 include/net/bluetooth/hci_core.h:2082 le_conn_complete_evt+0xcd3/0x1220 net/bluetooth/hci_event.c:5771 hci_le_conn_complete_evt+0x187/0x450 net/bluetooth/hci_event.c:5797 hci_event_func net/bluetooth/hci_event.c:7542 [inline] hci_event_packet+0x78f/0x1200 net/bluetooth/hci_event.c:7599 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4071 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 5835: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x1a8/0x320 mm/slub.c:4407 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] l2cap_chan_create+0x50/0x780 net/bluetooth/l2cap_core.c:445 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1906 [inline] l2cap_sock_new_connection_cb+0x182/0x2b0 net/bluetooth/l2cap_sock.c:1485 l2cap_connect_cfm+0x377/0x1040 net/bluetooth/l2cap_core.c:7287 hci_connect_cfm+0x92/0x140 include/net/bluetooth/hci_core.h:2082 le_conn_complete_evt+0xcd3/0x1220 net/bluetooth/hci_event.c:5771 hci_le_conn_complete_evt+0x187/0x450 net/bluetooth/hci_event.c:5797 hci_event_func net/bluetooth/hci_event.c:7542 [inline] hci_event_packet+0x78f/0x1200 net/bluetooth/hci_event.c:7599 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4071 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 12102: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kfree+0x195/0x550 mm/slub.c:4894 l2cap_sock_cleanup_listen+0xea/0x3e0 net/bluetooth/l2cap_sock.c:1468 l2cap_sock_release+0x6a/0x230 net/bluetooth/l2cap_sock.c:1426 __sock_release net/socket.c:649 [inline] sock_close+0xc3/0x240 net/socket.c:1439 __fput+0x458/0xa80 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6b5/0x2300 kernel/exit.c:961 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 get_signal+0x125e/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880288a9000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1280 bytes inside of freed 2048-byte region [ffff8880288a9000, ffff8880288a9800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x288a8 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 ffff888019842000 ffffea0000f13600 dead000000000002 raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 head: 0080000000000040 ffff888019842000 ffffea0000f13600 dead000000000002 head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 head: 0080000000000003 ffffea0000a22a01 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1460, tgid 1460 (kworker/u8:8), ts 102158218792, free_ts 102011951497 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x2119/0x21b0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2492 [inline] allocate_slab+0x8a/0x370 mm/slub.c:2660 new_slab mm/slub.c:2714 [inline] ___slab_alloc+0x8d1/0xdc0 mm/slub.c:3901 __slab_alloc mm/slub.c:3992 [inline] __slab_alloc_node mm/slub.c:4067 [inline] slab_alloc_node mm/slub.c:4228 [inline] __do_kmalloc_node mm/slub.c:4375 [inline] __kmalloc_node_track_caller_noprof+0x14c/0x450 mm/slub.c:4395 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:600 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:669 alloc_skb include/linux/skbuff.h:1336 [inline] nlmsg_new include/net/netlink.h:1055 [inline] inet6_ifinfo_notify+0x70/0x120 net/ipv6/addrconf.c:6179 addrconf_notify+0xc4e/0x1010 net/ipv6/addrconf.c:3760 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 netif_state_change+0x284/0x3a0 net/core/dev.c:1583 linkwatch_do_dev+0x117/0x170 net/core/link_watch.c:186 __linkwatch_run_queue+0x56d/0x7e0 net/core/link_watch.c:244 linkwatch_event+0x4c/0x60 net/core/link_watch.c:304 page last free pid 5836 tgid 5836 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0xb59/0xce0 mm/page_alloc.c:2895 discard_slab mm/slub.c:2758 [inline] __put_partials+0x159/0x1a0 mm/slub.c:3223 __slab_free+0x2b3/0x390 mm/slub.c:4565 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4191 [inline] slab_alloc_node mm/slub.c:4240 [inline] __do_kmalloc_node mm/slub.c:4375 [inline] __kmalloc_node_noprof+0x1b0/0x460 mm/slub.c:4382 kmalloc_node_noprof include/linux/slab.h:932 [inline] qdisc_alloc+0x9c/0xac0 net/sched/sch_generic.c:950 qdisc_create_dflt+0x8e/0x4e0 net/sched/sch_generic.c:1012 attach_one_default_qdisc net/sched/sch_generic.c:1178 [inline] netdev_for_each_tx_queue include/linux/netdevice.h:2660 [inline] attach_default_qdiscs net/sched/sch_generic.c:1196 [inline] dev_activate+0x378/0x1150 net/sched/sch_generic.c:1255 __dev_open+0x69c/0x880 net/core/dev.c:1691 __dev_change_flags+0x1ea/0x6d0 net/core/dev.c:9549 netif_change_flags+0x88/0x1a0 net/core/dev.c:9612 do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3143 rtnl_changelink net/core/rtnetlink.c:3761 [inline] __rtnl_newlink net/core/rtnetlink.c:3920 [inline] rtnl_newlink+0x160b/0x1c70 net/core/rtnetlink.c:4057 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6946 Memory state around the buggy address: ffff8880288a9400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880288a9480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880288a9500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880288a9580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880288a9600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================