================================================================== BUG: KASAN: slab-use-after-free in l2cap_sock_new_connection_cb+0x22a/0x240 net/bluetooth/l2cap_sock.c:1500 Read of size 8 at addr ffff888056ab2590 by task kworker/u9:0/11446 CPU: 1 UID: 0 PID: 11446 Comm: kworker/u9:0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: hci2 hci_rx_work Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 l2cap_sock_new_connection_cb+0x22a/0x240 net/bluetooth/l2cap_sock.c:1500 l2cap_connect_cfm+0x4c7/0xf80 net/bluetooth/l2cap_core.c:7287 hci_connect_cfm include/net/bluetooth/hci_core.h:2103 [inline] le_conn_complete_evt+0x1ba3/0x2150 net/bluetooth/hci_event.c:5795 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5821 hci_le_meta_evt+0x354/0x5e0 net/bluetooth/hci_event.c:7258 hci_event_func net/bluetooth/hci_event.c:7566 [inline] hci_event_packet+0x685/0x11c0 net/bluetooth/hci_event.c:7623 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4071 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 11446: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4376 [inline] __kmalloc_noprof+0x223/0x510 mm/slub.c:4388 kmalloc_noprof include/linux/slab.h:909 [inline] sk_prot_alloc+0x1a8/0x2a0 net/core/sock.c:2239 sk_alloc+0x36/0xc20 net/core/sock.c:2295 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:151 l2cap_sock_alloc.constprop.0+0x33/0x1d0 net/bluetooth/l2cap_sock.c:1897 l2cap_sock_new_connection_cb+0x101/0x240 net/bluetooth/l2cap_sock.c:1485 l2cap_connect_cfm+0x4c7/0xf80 net/bluetooth/l2cap_core.c:7287 hci_connect_cfm include/net/bluetooth/hci_core.h:2103 [inline] le_conn_complete_evt+0x1ba3/0x2150 net/bluetooth/hci_event.c:5795 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5821 hci_le_meta_evt+0x354/0x5e0 net/bluetooth/hci_event.c:7258 hci_event_func net/bluetooth/hci_event.c:7566 [inline] hci_event_packet+0x685/0x11c0 net/bluetooth/hci_event.c:7623 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4071 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 11709: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x60/0x70 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+0x2b4/0x4d0 mm/slub.c:4894 sk_prot_free net/core/sock.c:2278 [inline] __sk_destruct+0x75f/0x9a0 net/core/sock.c:2373 sk_destruct+0xc2/0xf0 net/core/sock.c:2401 __sk_free+0xf4/0x3e0 net/core/sock.c:2412 sk_free+0x6a/0x90 net/core/sock.c:2423 sock_put include/net/sock.h:1962 [inline] l2cap_sock_kill net/bluetooth/l2cap_sock.c:1265 [inline] l2cap_sock_kill+0x171/0x2d0 net/bluetooth/l2cap_sock.c:1250 l2cap_sock_cleanup_listen+0x3d/0x2a0 net/bluetooth/l2cap_sock.c:1465 l2cap_sock_release+0x69/0x250 net/bluetooth/l2cap_sock.c:1426 __sock_release+0xb0/0x270 net/socket.c:649 sock_close+0x1c/0x30 net/socket.c:1439 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x150/0x240 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x86f/0x2bf0 kernel/exit.c:961 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 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+0x41c/0x4e0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888056ab2000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1424 bytes inside of freed 2048-byte region [ffff888056ab2000, ffff888056ab2800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x56ab0 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 ffff88801b842000 ffffea0000c56e00 dead000000000002 raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b842000 ffffea0000c56e00 dead000000000002 head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea00015aac01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5916, tgid 5916 (kworker/1:4), ts 63611270920, free_ts 15338207879 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2492 [inline] allocate_slab mm/slub.c:2660 [inline] new_slab+0x247/0x330 mm/slub.c:2714 ___slab_alloc+0xcf2/0x1750 mm/slub.c:3901 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3992 __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+0x2ee/0x510 mm/slub.c:4395 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:600 __alloc_skb+0x166/0x380 net/core/skbuff.c:669 alloc_skb include/linux/skbuff.h:1336 [inline] mld_newpack.isra.0+0x18e/0xa20 net/ipv6/mcast.c:1780 add_grhead+0x299/0x340 net/ipv6/mcast.c:1891 add_grec+0x11b5/0x1720 net/ipv6/mcast.c:2030 mld_send_cr net/ipv6/mcast.c:2153 [inline] mld_ifc_work+0x41f/0xbf0 net/ipv6/mcast.c:2698 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 page last free pid 1 tgid 1 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895 __free_pages mm/page_alloc.c:5260 [inline] free_contig_range+0x183/0x4b0 mm/page_alloc.c:7091 destroy_args+0x794/0xc10 mm/debug_vm_pgtable.c:958 debug_vm_pgtable+0x1a32/0x3640 mm/debug_vm_pgtable.c:1345 do_one_initcall+0x120/0x6e0 init/main.c:1269 do_initcall_level init/main.c:1331 [inline] do_initcalls init/main.c:1347 [inline] do_basic_setup init/main.c:1366 [inline] kernel_init_freeable+0x5c2/0x910 init/main.c:1579 kernel_init+0x1c/0x2b0 init/main.c:1469 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888056ab2480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888056ab2500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888056ab2580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888056ab2600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888056ab2680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================