================================================================== BUG: KASAN: use-after-free in hci_chan_del+0x14f/0x190 net/bluetooth/hci_conn.c:1728 Read of size 8 at addr ffff8880a5ff6c18 by task syz-executor.0/6869 CPU: 0 PID: 6869 Comm: syz-executor.0 Not tainted 5.8.0-rc7-next-20200731-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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 hci_chan_del+0x14f/0x190 net/bluetooth/hci_conn.c:1728 l2cap_conn_del+0x61b/0x9e0 net/bluetooth/l2cap_core.c:1900 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:8160 [inline] l2cap_disconn_cfm+0x85/0xa0 net/bluetooth/l2cap_core.c:8153 hci_disconn_cfm include/net/bluetooth/hci_core.h:1438 [inline] hci_conn_hash_flush+0x114/0x220 net/bluetooth/hci_conn.c:1557 hci_dev_do_close+0x5c6/0x1080 net/bluetooth/hci_core.c:1770 hci_unregister_dev+0x1bd/0xe30 net/bluetooth/hci_core.c:3790 vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:135 exit_task_work include/linux/task_work.h:25 [inline] do_exit+0xb7d/0x29f0 kernel/exit.c:806 do_group_exit+0x125/0x310 kernel/exit.c:903 __do_sys_exit_group kernel/exit.c:914 [inline] __se_sys_exit_group kernel/exit.c:912 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:912 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45ccd9 Code: Bad RIP value. RSP: 002b:00007fff1883ac88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045ccd9 RDX: 0000000000416731 RSI: 0000000000ca85f0 RDI: 0000000000000043 RBP: 00000000004c2963 R08: 000000000000000b R09: 0000000000000000 R10: 0000000001d3e940 R11: 0000000000000246 R12: 0000000000000003 R13: 00007fff1883add0 R14: 0000000000104bd1 R15: 00007fff1883ade0 Allocated by task 3907: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 kmem_cache_alloc_trace+0x16e/0x2c0 mm/slab.c:3550 kmalloc include/linux/slab.h:554 [inline] kernfs_get_open_node fs/kernfs/file.c:571 [inline] kernfs_fop_open+0x957/0xd40 fs/kernfs/file.c:717 do_dentry_open+0x4b9/0x11b0 fs/open.c:827 do_open fs/namei.c:3249 [inline] path_openat+0x1b9a/0x2730 fs/namei.c:3366 do_filp_open+0x17e/0x3c0 fs/namei.c:3393 do_sys_openat2+0x16d/0x420 fs/open.c:1178 do_sys_open fs/open.c:1194 [inline] __do_sys_open fs/open.c:1202 [inline] __se_sys_open fs/open.c:1198 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1198 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 3907: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kfree+0x103/0x2c0 mm/slab.c:3756 kernfs_fop_release+0xe3/0x190 fs/kernfs/file.c:779 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:135 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:139 [inline] exit_to_user_mode_prepare+0x195/0x1c0 kernel/entry/common.c:166 syscall_exit_to_user_mode+0x59/0x2b0 kernel/entry/common.c:241 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8880a5ff6c00 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 24 bytes inside of 128-byte region [ffff8880a5ff6c00, ffff8880a5ff6c80) The buggy address belongs to the page: page:00000000bd0fe72b refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a5ff6e00 pfn:0xa5ff6 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea0002798e88 ffffea0002520fc8 ffff8880aa000400 raw: ffff8880a5ff6e00 ffff8880a5ff6000 000000010000000d 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a5ff6b00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a5ff6b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880a5ff6c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a5ff6c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a5ff6d00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================