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    SubjectRe: KASAN: use-after-free Read in device_release_driver_internal
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    Am Dienstag, den 06.08.2019, 14:50 +0200 schrieb Andrey Konovalov:
    > On Tue, Aug 6, 2019 at 2:36 PM Oliver Neukum <oneukum@suse.com> wrote:
    > >
    > > Am Donnerstag, den 01.08.2019, 14:47 -0400 schrieb Alan Stern:
    > > >
    > > > I think this must be caused by an unbalanced refcount. That is,
    > > > something must drop one more reference to the device than it takes.
    > > > That would explain why the invalid access occurs inside a single
    > > > bus_remove_device() call, between the klist_del() and
    > > > device_release_driver().
    > > >
    > > > The kernel log indicates that the device was probed by rndis_wlan,
    > > > rndis_host, and cdc_acm, all of which got errors because of the
    > > > device's bogus descriptors. Probably one of them is messing up the
    > > > refcount.
    > >
    > > Hi,
    > >
    > > you made me look at cdc-acm. I suspect
    > >
    > > cae2bc768d176bfbdad7035bbcc3cdc973eb7984 ("usb: cdc-acm: Decrement tty port's refcount if probe() fail")
    > >
    > > is buggy decrementing the refcount on the interface in destroy()
    > > even before the refcount is increased.
    > >
    > > Unfortunately I cannot tell from the bug report how many and which
    > > interfaces the emulated test device has. Hence it is unclear to me,
    > > when exactly probe() would fail cdc-acm.
    > >
    > > If you agree. I am attaching a putative fix.
    >
    > Let's see if it fixes the issue.
    >
    > #syz fix: https://github.com/google/kasan.git 6a3599ce

    Hi,

    did this ever produce a result? I saw none.

    Regards
    Oliver

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