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From:   Josh Gao <jmgao@google.com>
Date:   Tue, 19 Mar 2019 22:59:05 -0700
Message-ID: <CAAHfpN_uVBR5X7e4Bb=OsMVqudB9rVD7rqLhTfix6Pa+-iVwWw@mail.gmail.com>
Subject: Re: [PATCH V2] usb: gadget: f_fs: don't free buffer prematurely
To:     fei.yang@intel.com
Cc:     balbi@kernel.org, gregkh@linuxfoundation.org,
        Jerry Zhang <zhangjerry@google.com>, andrzej.p@collabora.com,
        plr.vincent@gmail.com, jingx.shen@intel.com,
        John Stultz <john.stultz@linaro.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
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On Tue, Mar 19, 2019 at 10:56 PM Josh Gao <jmgao@google.com> wrote:
>
> On Tue, Mar 19, 2019 at 10:32 PM <fei.yang@intel.com> wrote:
> >
> > From: Fei Yang <fei.yang@intel.com>
> >
> > The following kernel panic happens due to the io_data buffer gets deallocated
> > before the async io is completed. Add a check for the case where io_data buffer
> > should be deallocated by ffs_user_copy_worker.
>
> It looks like this happened because data got renamed to io_data, which made the
> `data = NULL` marked with "Do not kfree the buffer in this function" not do
> what it was hoping. This should probably either delete the assignment above or
> fix the assignment to refer to io_data? (EIOCBQUEUED presumably can't come from
> elsewhere?)

(except ffs_free_buffer doesn't check for null, so probably the former)