================================================================== BUG: KASAN: use-after-free in rfcomm_dlc_get net/bluetooth/rfcomm/core.c:360 [inline] BUG: KASAN: use-after-free in rfcomm_dlc_exists+0x17d/0x1a0 net/bluetooth/rfcomm/core.c:550 Read of size 1 at addr ffff888076f80544 by task syz-executor.3/7533 CPU: 0 PID: 7533 Comm: syz-executor.3 Not tainted 5.6.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:641 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:132 rfcomm_dlc_get net/bluetooth/rfcomm/core.c:360 [inline] rfcomm_dlc_exists+0x17d/0x1a0 net/bluetooth/rfcomm/core.c:550 __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:413 [inline] rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline] rfcomm_dev_ioctl+0x9ff/0x1e80 net/bluetooth/rfcomm/tty.c:588 rfcomm_sock_ioctl+0x90/0xb0 net/bluetooth/rfcomm/sock.c:902 sock_do_ioctl+0xd8/0x2f0 net/socket.c:1053 sock_ioctl+0x3ed/0x790 net/socket.c:1204 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x123/0x180 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c449 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7f415cbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f7f415cc6d4 RCX: 000000000045c449 RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 0000000000000004 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000317 R14: 00000000004c53d7 R15: 000000000076bf2c Allocated by task 16488: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:515 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] rfcomm_dlc_alloc+0x82/0x410 net/bluetooth/rfcomm/core.c:305 rfcomm_sock_alloc.constprop.0+0xb3/0x380 net/bluetooth/rfcomm/sock.c:286 rfcomm_sock_create+0xf3/0x2b0 net/bluetooth/rfcomm/sock.c:329 bt_sock_create+0x16a/0x2d0 net/bluetooth/af_bluetooth.c:130 __sock_create+0x3ce/0x730 net/socket.c:1433 sock_create net/socket.c:1484 [inline] __sys_socket+0x103/0x220 net/socket.c:1526 __do_sys_socket net/socket.c:1535 [inline] __se_sys_socket net/socket.c:1533 [inline] __x64_sys_socket+0x73/0xb0 net/socket.c:1533 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7391: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x2c0 mm/slab.c:3757 rfcomm_dlc_free+0x20/0x30 net/bluetooth/rfcomm/core.c:328 rfcomm_dlc_put include/net/bluetooth/rfcomm.h:258 [inline] __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:417 [inline] rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline] rfcomm_dev_ioctl+0x1b9d/0x1e80 net/bluetooth/rfcomm/tty.c:588 rfcomm_sock_ioctl+0x90/0xb0 net/bluetooth/rfcomm/sock.c:902 sock_do_ioctl+0xd8/0x2f0 net/socket.c:1053 sock_ioctl+0x3ed/0x790 net/socket.c:1204 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x123/0x180 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888076f80400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 324 bytes inside of 512-byte region [ffff888076f80400, ffff888076f80600) The buggy address belongs to the page: page:ffffea0001dbe000 refcount:1 mapcount:0 mapping:ffff8880aa400a80 index:0xffff888076f80000 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea000155c2c8 ffffea00028a0a88 ffff8880aa400a80 raw: ffff888076f80000 ffff888076f80000 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888076f80400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888076f80480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888076f80500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888076f80580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888076f80600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================