================================================================== BUG: KASAN: slab-use-after-free in l2cap_sock_ready_cb+0x1a9/0x1b0 net/bluetooth/l2cap_sock.c:1787 Read of size 8 at addr ffff888026a0b188 by task kworker/u34:1/27626 CPU: 3 UID: 0 PID: 27626 Comm: kworker/u34:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: hci4 hci_rx_work 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 l2cap_sock_ready_cb+0x1a9/0x1b0 net/bluetooth/l2cap_sock.c:1787 l2cap_chan_ready net/bluetooth/l2cap_core.c:1291 [inline] l2cap_le_start+0x1ea/0xd20 net/bluetooth/l2cap_core.c:1420 l2cap_conn_ready net/bluetooth/l2cap_core.c:1673 [inline] l2cap_connect_cfm+0x88e/0xf20 net/bluetooth/l2cap_core.c:7580 hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline] le_conn_complete_evt+0x197c/0x1f60 net/bluetooth/hci_event.c:5853 hci_le_conn_complete_evt+0x23c/0x3a0 net/bluetooth/hci_event.c:5879 hci_le_meta_evt+0x34a/0x5f0 net/bluetooth/hci_event.c:7517 hci_event_func net/bluetooth/hci_event.c:7781 [inline] hci_event_packet+0x51c/0xcd0 net/bluetooth/hci_event.c:7835 hci_rx_work+0x451/0xfc0 net/bluetooth/hci_core.c:4039 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 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 Allocated by task 27895: 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:5334 [inline] __kmalloc_noprof+0x322/0x820 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] sk_prot_alloc+0x10b/0x2a0 net/core/sock.c:2251 sk_alloc+0x36/0xe80 net/core/sock.c:2307 bt_sock_alloc+0x3b/0x3c0 net/bluetooth/af_bluetooth.c:148 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1980 [inline] l2cap_sock_create+0x144/0x340 net/bluetooth/l2cap_sock.c:2018 bt_sock_create+0x185/0x350 net/bluetooth/af_bluetooth.c:132 __sock_create+0x339/0x860 net/socket.c:1651 sock_create net/socket.c:1709 [inline] __sys_socket_create net/socket.c:1746 [inline] __sys_socket+0x14d/0x260 net/socket.c:1793 __do_sys_socket net/socket.c:1807 [inline] __se_sys_socket net/socket.c:1805 [inline] __ia32_sys_socket+0x72/0xb0 net/socket.c:1805 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe7/0x970 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 27895: 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:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x22b/0x6c0 mm/slub.c:6692 sk_prot_free net/core/sock.c:2290 [inline] __sk_destruct+0x88c/0xab0 net/core/sock.c:2390 sk_destruct+0xc8/0xf0 net/core/sock.c:2418 __sk_free+0xf4/0x3e0 net/core/sock.c:2429 sk_free+0x61/0x90 net/core/sock.c:2440 sock_put include/net/sock.h:2020 [inline] l2cap_sock_kill net/bluetooth/l2cap_sock.c:1319 [inline] l2cap_sock_kill+0x187/0x2a0 net/bluetooth/l2cap_sock.c:1308 l2cap_sock_release+0x1cb/0x280 net/bluetooth/l2cap_sock.c:1492 __sock_release+0xb3/0x260 net/socket.c:710 sock_close+0x1c/0x30 net/socket.c:1501 __fput+0x3ff/0xb50 fs/file_table.c:512 task_work_run+0x150/0x240 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:70 [inline] exit_to_user_mode_loop+0x1d8/0x6f0 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_fast_syscall_32+0x701/0x970 arch/x86/entry/syscall_32.c:310 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff888026a0b000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 392 bytes inside of freed 2048-byte region [ffff888026a0b000, ffff888026a0b800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26a08 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 ffff88801bc42f00 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801bc42f00 dead000000000100 dead000000000122 head: 0000000000000000 0000000800080008 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5732, tgid 5732 (syz-executor), ts 48238864150, free_ts 45519029886 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab mm/slub.c:3380 [inline] new_slab+0xa2/0x640 mm/slub.c:3426 refill_objects+0xe3/0x410 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] batadv_hardif_add_interface net/batman-adv/hard-interface.c:878 [inline] batadv_hard_if_event+0x14bf/0x3870 net/batman-adv/hard-interface.c:1087 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2250 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline] call_netdevice_notifiers net/core/dev.c:2302 [inline] register_netdevice+0x1998/0x25a0 net/core/dev.c:11484 veth_newlink+0x316/0xa00 drivers/net/veth.c:1863 rtnl_newlink_create net/core/rtnetlink.c:3913 [inline] __rtnl_newlink net/core/rtnetlink.c:4044 [inline] rtnl_newlink+0x1499/0x2380 net/core/rtnetlink.c:4159 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:7076 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345 page last free pid 5697 tgid 5697 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950 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_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4584 [inline] slab_alloc_node mm/slub.c:4917 [inline] kmem_cache_alloc_node_noprof+0x27d/0x6b0 mm/slub.c:4989 __alloc_skb+0x140/0x710 net/core/skbuff.c:704 alloc_skb_fclone include/linux/skbuff.h:1434 [inline] tcp_stream_alloc_skb+0x34/0x660 net/ipv4/tcp.c:931 tcp_sendmsg_locked+0x13b2/0x44d0 net/ipv4/tcp.c:1256 tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1451 inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:865 sock_sendmsg_nosec net/socket.c:775 [inline] __sock_sendmsg net/socket.c:790 [inline] sock_write_iter+0x4ea/0x5b0 net/socket.c:1241 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x1f8/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888026a0b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888026a0b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888026a0b180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888026a0b200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888026a0b280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================