================================================================== 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 ffff888055af3188 by task kworker/u34:8/5751 CPU: 2 UID: 0 PID: 5751 Comm: kworker/u34:8 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: hci2 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:7575 hci_connect_cfm include/net/bluetooth/hci_core.h:2137 [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 9687: 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:5362 [inline] __kmalloc_noprof+0x322/0x820 mm/slub.c:5387 _kmalloc_noprof include/linux/slab.h:973 [inline] sk_prot_alloc+0x10b/0x2a0 net/core/sock.c:2252 sk_alloc+0x36/0xe80 net/core/sock.c:2308 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] __x64_sys_socket+0x72/0xb0 net/socket.c:1805 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 9686: 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:2705 [inline] slab_free mm/slub.c:6405 [inline] kfree+0x22b/0x6c0 mm/slub.c:6720 sk_prot_free net/core/sock.c:2291 [inline] __sk_destruct+0x88c/0xab0 net/core/sock.c:2391 sk_destruct+0xc8/0xf0 net/core/sock.c:2419 __sk_free+0xf4/0x3e0 net/core/sock.c:2430 sk_free+0x61/0x90 net/core/sock.c:2441 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_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888055af3000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 392 bytes inside of freed 2048-byte region [ffff888055af3000, ffff888055af3800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x55af0 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 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5740, tgid 5740 (syz-executor), ts 48029754692, free_ts 0 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:3294 [inline] allocate_slab mm/slub.c:3408 [inline] new_slab+0xa2/0x650 mm/slub.c:3454 refill_objects+0xe3/0x410 mm/slub.c:7338 refill_sheaf mm/slub.c:2832 [inline] __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4703 alloc_from_pcs mm/slub.c:4801 [inline] slab_alloc_node mm/slub.c:4933 [inline] __do_kmalloc_node mm/slub.c:5361 [inline] __kmalloc_node_track_caller_noprof+0x679/0x830 mm/slub.c:5497 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:637 pskb_expand_head+0x249/0x10e0 net/core/skbuff.c:2306 netlink_trim+0x22d/0x2f0 net/netlink/af_netlink.c:1300 netlink_broadcast_filtered+0x6d/0xf20 net/netlink/af_netlink.c:1518 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xb1/0x290 net/netlink/af_netlink.c:2599 rtnl_notify net/core/rtnetlink.c:963 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:4553 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4569 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:4556 [inline] rtnetlink_event+0x1b3/0x1f0 net/core/rtnetlink.c:7136 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2250 __netdev_upper_dev_link+0x43c/0x7e0 net/core/dev.c:8939 page_owner free stack trace missing Memory state around the buggy address: ffff888055af3080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888055af3100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888055af3180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888055af3200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888055af3280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================