Re: [PATCH v2] tty: fix data race in flush_to_ldisc

[Peter Hurley]

On Thu, Sep 17, 2015 at 8:53 AM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, Sep 17, 2015 at 12:39:36PM +0200, Dmitry Vyukov wrote:
>> flush_to_ldisc reads port->itty and checks that it is not NULL,
>> concurrently release_tty sets port->itty to NULL. It is possible
>> that flush_to_ldisc loads port->itty once, ensures that it is
>> not NULL, but then reloads it again and uses. The second load
>> can already return NULL, which will cause a crash.
>>
>> Use READ_ONCE to read port->itty.
>>
>> The data race was found with KernelThreadSanitizer (KTSAN).
>>
>> Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
>
> You sent 3 patches here, but no hint as to what order they need to be
> applied in.  Please resend them as a patch series (i.e. 1/3, 2/3, 3/3)
> so they can be applied correctly.

Greg,

I don't think these 3 patches are dependent on each other; I think they
can be applied in any order.

Regards,
Peter Hurley
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/