Re: WARNING: ODEBUG bug in appledisplay_probe

[Andrey Konovalov]

On Tue, Sep 3, 2019 at 2:08 PM syzbot
<syzbot+5bb7a3b6f59db285e759@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    eea39f24 usb-fuzzer: main usb gadget fuzzer driver
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=101b49ea600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e
> dashboard link: https://syzkaller.appspot.com/bug?extid=5bb7a3b6f59db285e759
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=159cd5ea600000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16717666600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+5bb7a3b6f59db285e759@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> appledisplay 1-1:0.16: Error while getting initial brightness: -110
> ------------[ cut here ]------------
> ODEBUG: free active (active state 0) object type: timer_list hint:
> delayed_work_timer_fn+0x0/0x90 include/linux/topology.h:80
> WARNING: CPU: 0 PID: 12 at lib/debugobjects.c:481
> debug_print_object+0x160/0x250 lib/debugobjects.c:481
> Kernel panic - not syncing: panic_on_warn set ...
> CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc5+ #28
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Workqueue: usb_hub_wq hub_event
> Call Trace:
>   __dump_stack lib/dump_stack.c:77 [inline]
>   dump_stack+0xca/0x13e lib/dump_stack.c:113
>   panic+0x2a3/0x6da kernel/panic.c:219
>   __warn.cold+0x20/0x4a kernel/panic.c:576
>   report_bug+0x262/0x2a0 lib/bug.c:186
>   fixup_bug arch/x86/kernel/traps.c:179 [inline]
>   fixup_bug arch/x86/kernel/traps.c:174 [inline]
>   do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
>   do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
>   invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
> RIP: 0010:debug_print_object+0x160/0x250 lib/debugobjects.c:481
> Code: dd 80 ef da 85 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 bf 00 00 00 48
> 8b 14 dd 80 ef da 85 48 c7 c7 c0 e4 da 85 e8 e5 dd 31 ff <0f> 0b 83 05 4b
> 0f a8 05 01 48 83 c4 20 5b 5d 41 5c 41 5d c3 48 89
> RSP: 0018:ffff8881da20f140 EFLAGS: 00010282
> RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: ffffffff81288cfd RDI: ffffed103b441e1a
> RBP: 0000000000000001 R08: ffff8881da1f9800 R09: fffffbfff11ad79a
> R10: fffffbfff11ad799 R11: ffffffff88d6bccf R12: ffffffff86d0dc60
> R13: ffffffff812e7b70 R14: ffff8881d56f8f68 R15: ffff8881d4ee4578
>   __debug_check_no_obj_freed lib/debugobjects.c:963 [inline]
>   debug_check_no_obj_freed+0x2df/0x443 lib/debugobjects.c:994
>   slab_free_hook mm/slub.c:1420 [inline]
>   slab_free_freelist_hook mm/slub.c:1474 [inline]
>   slab_free mm/slub.c:3016 [inline]
>   kfree+0x20b/0x2f0 mm/slub.c:3957
>   appledisplay_probe+0x772/0xb37 drivers/usb/misc/appledisplay.c:312
>   usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
>   really_probe+0x281/0x6d0 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2165
>   usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
>   generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
>   usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
>   really_probe+0x281/0x6d0 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2165
>   usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
>   hub_port_connect drivers/usb/core/hub.c:5098 [inline]
>   hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
>   port_event drivers/usb/core/hub.c:5359 [inline]
>   hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
>   process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
>   worker_thread+0x96/0xe20 kernel/workqueue.c:2415
>   kthread+0x318/0x420 kernel/kthread.c:255
>   ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
> Kernel Offset: disabled
> Rebooting in 86400 seconds..
>
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx
>
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> syzbot can test patches for this bug, for details see:
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#syz dup: KASAN: use-after-free Read in appledisplay_bl_get_brightness