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Date:   Wed, 31 Jul 2019 08:54:25 -0700 (PDT)
Message-Id: <20190731.085425.835225391467422617.davem@davemloft.net>
To:     juliana.rodrigueiro@intra2net.com
Cc:     isdn@linux-pingi.de, netdev@vger.kernel.org,
        thomas.jarosch@intra2net.com
Subject: Re: [PATCH v2] isdn: hfcsusb: Fix mISDN driver crash caused by
 transfer buffer on the stack
From:   David Miller <davem@davemloft.net>
In-Reply-To: <2432092.e6oL0QVcq9@rocinante.m.i2n>
References: <2432092.e6oL0QVcq9@rocinante.m.i2n>
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From: Juliana Rodrigueiro <juliana.rodrigueiro@intra2net.com>
Date: Wed, 31 Jul 2019 15:17:23 +0200

> Since linux 4.9 it is not possible to use buffers on the stack for DMA transfers.
> 
> During usb probe the driver crashes with "transfer buffer is on stack" message.
> 
> This fix k-allocates a buffer to be used on "read_reg_atomic", which is a macro
> that calls "usb_control_msg" under the hood.
> 
> Kernel 4.19 backtrace:
 ...
> Signed-off-by: Juliana Rodrigueiro <juliana.rodrigueiro@intra2net.com>

Applied.