Hi Dmitry, >>>>>> syzbot found the following crash on: >>>>>> >>>>>> HEAD commit: 6d21a41b Add linux-next specific files for 20190718 >>>>>> git tree: linux-next >>>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=1377958fa00000 >>>>>> kernel config: https://syzkaller.appspot.com/x/.config?x=3430a151e1452331 >>>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=0abbda0523882250a97a >>>>>> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >>>>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=113e2bb7a00000 >>>>> >>>>> +drivers/bluetooth/hci_h5.c maintainers >>>>> >>>>>> IMPORTANT: if you fix the bug, please add the following tag to the commit: >>>>>> Reported-by: syzbot+0abbda0523882250a97a@xxxxxxxxxxxxxxxxxxxxxxxxx >>>>>> >>>>>> ================================================================== >>>>>> BUG: KASAN: use-after-free in h5_rx_3wire_hdr+0x35d/0x3c0 >>>>>> /drivers/bluetooth/hci_h5.c:438 >>>>>> Read of size 1 at addr ffff8880a161d1c8 by task syz-executor.4/12040 >>>>>> >>>>>> CPU: 1 PID: 12040 Comm: syz-executor.4 Not tainted 5.2.0-next-20190718 #41 >>>>>> 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+0x172/0x1f0 /lib/dump_stack.c:113 >>>>>> print_address_description.cold+0xd4/0x306 /mm/kasan/report.c:351 >>>>>> __kasan_report.cold+0x1b/0x36 /mm/kasan/report.c:482 >>>>>> kasan_report+0x12/0x17 /mm/kasan/common.c:612 >>>>>> __asan_report_load1_noabort+0x14/0x20 /mm/kasan/generic_report.c:129 >>>>>> h5_rx_3wire_hdr+0x35d/0x3c0 /drivers/bluetooth/hci_h5.c:438 >>>>>> h5_recv+0x32f/0x500 /drivers/bluetooth/hci_h5.c:563 >>>>>> hci_uart_tty_receive+0x279/0x790 /drivers/bluetooth/hci_ldisc.c:600 >>>>>> tiocsti /drivers/tty/tty_io.c:2197 [inline] >>>>>> tty_ioctl+0x949/0x14f0 /drivers/tty/tty_io.c:2573 >>>>>> vfs_ioctl /fs/ioctl.c:46 [inline] >>>>>> file_ioctl /fs/ioctl.c:509 [inline] >>>>>> do_vfs_ioctl+0xdb6/0x13e0 /fs/ioctl.c:696 >>>>>> ksys_ioctl+0xab/0xd0 /fs/ioctl.c:713 >>>>>> __do_sys_ioctl /fs/ioctl.c:720 [inline] >>>>>> __se_sys_ioctl /fs/ioctl.c:718 [inline] >>>>>> __x64_sys_ioctl+0x73/0xb0 /fs/ioctl.c:718 >>>>>> do_syscall_64+0xfd/0x6a0 /arch/x86/entry/common.c:296 >>>>>> entry_SYSCALL_64_after_hwframe+0x49/0xbe >>>>>> RIP: 0033:0x459819 >>>>>> Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 >>>>>> RSP: 002b:00007f7a3b459c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 >>>>>> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459819 >>>>>> RDX: 0000000020000080 RSI: 0000000000005412 RDI: 0000000000000003 >>>>>> RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 >>>>>> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7a3b45a6d4 >>>>>> R13: 00000000004c408a R14: 00000000004d7ff0 R15: 00000000ffffffff >>>> >>>> Is this happening on specific hardware? >>> >>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> >> funny ;) >> >> I meant the Bluetooth chip on this machine. > > I don't think there are any Bluetooth chips exposed in GCE VMs. I > would expect that this bug does not require any hardware to trigger. then this might be also the same bug as the other missing drivers->ops checking. See https://lore.kernel.org/linux-bluetooth/2E234F47-724D-4CFB-93B5-48E5BDA6F230@xxxxxxxxxxxx/ for a proposed patch. However I have the feeling that hci_h5.c needs to be added to this as well. Regards Marcel
