Hello, syzbot found the following issue on: HEAD commit: a804ab08 Add linux-next specific files for 20201006 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=1073270b900000 kernel config: https://syzkaller.appspot.com/x/.config?x=26c1b4cc4a62ccb dashboard link: https://syzkaller.appspot.com/bug?extid=1df6a63e69a359c8b517 compiler: gcc (GCC) 10.1.0-syz 20200507 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+1df6a63e69a359c8b517@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:1145 [inline] BUG: KASAN: use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:1115 [inline] BUG: KASAN: use-after-free in sco_chan_del+0x400/0x430 net/bluetooth/sco.c:149 Read of size 8 at addr ffff88804d29c918 by task syz-executor.2/27575 CPU: 0 PID: 27575 Comm: syz-executor.2 Not tainted 5.9.0-rc8-next-20201006-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+0x198/0x1fb lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 hci_conn_drop include/net/bluetooth/hci_core.h:1145 [inline] hci_conn_drop include/net/bluetooth/hci_core.h:1115 [inline] sco_chan_del+0x400/0x430 net/bluetooth/sco.c:149 __sco_sock_close+0x16e/0x5b0 net/bluetooth/sco.c:434 sco_sock_close net/bluetooth/sco.c:448 [inline] sco_sock_release+0x69/0x290 net/bluetooth/sco.c:1059 __sock_release+0xcd/0x280 net/socket.c:596 sock_close+0x18/0x20 net/socket.c:1277 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:141 get_signal+0xd89/0x1f00 kernel/signal.c:2561 arch_do_signal+0x82/0x2470 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0x194/0x1f0 kernel/entry/common.c:192 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:267 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45de29 Code: 0d b4 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fabeda51c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffffc RBX: 0000000000002200 RCX: 000000000045de29 RDX: 0000000000000008 RSI: 0000000020000080 RDI: 0000000000000006 RBP: 000000000118c158 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118c124 R13: 00007ffdb3c9529f R14: 00007fabeda529c0 R15: 000000000118c124 Allocated by task 27575: 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+0x1a0/0x480 mm/slab.c:3552 kmalloc include/linux/slab.h:554 [inline] kzalloc include/linux/slab.h:666 [inline] hci_conn_add+0x53/0x1330 net/bluetooth/hci_conn.c:525 hci_connect_sco+0x356/0x860 net/bluetooth/hci_conn.c:1283 sco_connect net/bluetooth/sco.c:241 [inline] sco_sock_connect+0x308/0x980 net/bluetooth/sco.c:588 __sys_connect_file+0x155/0x1a0 net/socket.c:1852 __sys_connect+0x161/0x190 net/socket.c:1869 __do_sys_connect net/socket.c:1879 [inline] __se_sys_connect net/socket.c:1876 [inline] __x64_sys_connect+0x6f/0xb0 net/socket.c:1876 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 26665: 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:3420 [inline] kfree+0x10e/0x2a0 mm/slab.c:3758 device_release+0x9f/0x240 drivers/base/core.c:1808 kobject_cleanup lib/kobject.c:705 [inline] kobject_release lib/kobject.c:736 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x171/0x270 lib/kobject.c:753 put_device+0x1b/0x30 drivers/base/core.c:3037 hci_conn_del+0x27e/0x6a0 net/bluetooth/hci_conn.c:645 hci_conn_hash_flush+0x189/0x220 net/bluetooth/hci_conn.c:1558 hci_dev_do_close+0x5c6/0x1080 net/bluetooth/hci_core.c:1770 hci_unregister_dev+0x214/0xe90 net/bluetooth/hci_core.c:3827 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:141 exit_task_work include/linux/task_work.h:25 [inline] do_exit+0xb23/0x2930 kernel/exit.c:806 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1f00 kernel/signal.c:2757 arch_do_signal+0x82/0x2470 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0x194/0x1f0 kernel/entry/common.c:192 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:267 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88804d29c000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 2328 bytes inside of 4096-byte region [ffff88804d29c000, ffff88804d29d000) The buggy address belongs to the page: page:0000000084eedba7 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4d29c head:0000000084eedba7 order:1 compound_mapcount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea00012af708 ffffea0001001308 ffff8880aa040900 raw: 0000000000000000 ffff88804d29c000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88804d29c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804d29c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88804d29c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88804d29c980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804d29ca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. 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