================================================================== BUG: KASAN: slab-use-after-free in l2cap_sock_new_connection_cb+0x22a/0x240 net/bluetooth/l2cap_sock.c:1497 Read of size 8 at addr ffff888062b80588 by task kworker/u9:0/54 CPU: 0 UID: 0 PID: 54 Comm: kworker/u9:0 Not tainted 6.15.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: hci5 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:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 l2cap_sock_new_connection_cb+0x22a/0x240 net/bluetooth/l2cap_sock.c:1497 l2cap_connect_cfm+0x4c4/0xf80 net/bluetooth/l2cap_core.c:7262 hci_connect_cfm include/net/bluetooth/hci_core.h:2053 [inline] le_conn_complete_evt+0x1662/0x1d70 net/bluetooth/hci_event.c:5790 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5816 hci_le_meta_evt+0x2f6/0x5e0 net/bluetooth/hci_event.c:7186 hci_event_func net/bluetooth/hci_event.c:7494 [inline] hci_event_packet+0x66c/0x1190 net/bluetooth/hci_event.c:7549 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4020 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 54: 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:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4327 [inline] __kmalloc_noprof+0x223/0x510 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:909 [inline] sk_prot_alloc+0x1a8/0x2a0 net/core/sock.c:2198 sk_alloc+0x36/0xc20 net/core/sock.c:2254 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:148 l2cap_sock_alloc.constprop.0+0x33/0x1d0 net/bluetooth/l2cap_sock.c:1891 l2cap_sock_new_connection_cb+0x101/0x240 net/bluetooth/l2cap_sock.c:1482 l2cap_connect_cfm+0x4c4/0xf80 net/bluetooth/l2cap_core.c:7262 hci_connect_cfm include/net/bluetooth/hci_core.h:2053 [inline] le_conn_complete_evt+0x1662/0x1d70 net/bluetooth/hci_event.c:5790 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5816 hci_le_meta_evt+0x2f6/0x5e0 net/bluetooth/hci_event.c:7186 hci_event_func net/bluetooth/hci_event.c:7494 [inline] hci_event_packet+0x66c/0x1190 net/bluetooth/hci_event.c:7549 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4020 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 7484: 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:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2380 [inline] slab_free mm/slub.c:4642 [inline] kfree+0x2b6/0x4d0 mm/slub.c:4841 sk_prot_free net/core/sock.c:2237 [inline] __sk_destruct+0x740/0x980 net/core/sock.c:2332 sk_destruct+0xc2/0xf0 net/core/sock.c:2360 __sk_free+0xf4/0x3e0 net/core/sock.c:2371 sk_free+0x6a/0x90 net/core/sock.c:2382 sock_put include/net/sock.h:1944 [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:1462 l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1425 __sock_release+0xb0/0x270 net/socket.c:647 sock_close+0x1c/0x30 net/socket.c:1391 __fput+0x3ff/0xb70 fs/file_table.c:465 task_work_run+0x150/0x240 kernel/task_work.c:227 get_signal+0x1d1/0x26d0 kernel/signal.c:2807 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888062b80000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1416 bytes inside of freed 2048-byte region [ffff888062b80000, ffff888062b80800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x62b80 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 ffff88801b442000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b442000 dead000000000100 dead000000000122 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea00018ae001 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 5811, tgid 5811 (syz-executor), ts 61288562900, free_ts 15783751190 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1714 prep_new_page mm/page_alloc.c:1722 [inline] get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3684 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4966 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2450 [inline] allocate_slab mm/slub.c:2618 [inline] new_slab+0x244/0x340 mm/slub.c:2672 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948 __slab_alloc_node mm/slub.c:4023 [inline] slab_alloc_node mm/slub.c:4184 [inline] __do_kmalloc_node mm/slub.c:4326 [inline] __kmalloc_node_track_caller_noprof+0x2ee/0x510 mm/slub.c:4346 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:599 pskb_expand_head+0x22d/0x10b0 net/core/skbuff.c:2247 netlink_trim+0x22d/0x310 net/netlink/af_netlink.c:1295 netlink_broadcast_filtered+0xca/0xf10 net/netlink/af_netlink.c:1501 nlmsg_multicast_filtered include/net/netlink.h:1129 [inline] nlmsg_multicast include/net/netlink.h:1148 [inline] nlmsg_notify+0x9e/0x220 net/netlink/af_netlink.c:2577 rtnl_notify net/core/rtnetlink.c:958 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:4429 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4445 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4432 [inline] rtmsg_ifinfo+0x174/0x1a0 net/core/rtnetlink.c:4451 register_netdevice+0x1bdd/0x2270 net/core/dev.c:11052 register_netdev+0x34/0x50 net/core/dev.c:11116 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:1258 [inline] __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2721 __free_pages mm/page_alloc.c:5078 [inline] free_contig_range+0x135/0x3f0 mm/page_alloc.c:6934 destroy_args+0x66f/0x830 mm/debug_vm_pgtable.c:1017 debug_vm_pgtable+0x130e/0x2d50 mm/debug_vm_pgtable.c:1397 do_one_initcall+0x120/0x6e0 init/main.c:1257 do_initcall_level init/main.c:1319 [inline] do_initcalls init/main.c:1335 [inline] do_basic_setup init/main.c:1354 [inline] kernel_init_freeable+0x5c2/0x900 init/main.c:1567 kernel_init+0x1c/0x2b0 init/main.c:1457 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888062b80480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888062b80500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888062b80580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888062b80600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888062b80680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================