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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Thu, 14 May 2020 08:19:23 +0200
Message-ID: <CACT4Y+Y3g+NCCLP_twHeU9+Q=MfrRM4OrDQFFTGXsE=s2kKXYA@mail.gmail.com>
Subject: Re: WARNING in memtype_reserve
To:     Christoph Hellwig <hch@lst.de>
Cc:     Hillf Danton <hdanton@sina.com>,
        syzbot <syzbot+353be47c9ce21b68b7ed@syzkaller.appspotmail.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        Thomas Gleixner <tglx@linutronix.de>, jeremy.linton@arm.com,
        LKML <linux-kernel@vger.kernel.org>,
        USB list <linux-usb@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        "the arch/x86 maintainers" <x86@kernel.org>
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On Thu, May 14, 2020 at 8:14 AM Christoph Hellwig <hch@lst.de> wrote:
>
> Guys, can you please start formal thread on this?  I have no
> idea where this came from and what the rationale is.  Btw, if the
> pfn is crap in dma_direct_mmap then the dma_addr_t passed in is
> crap, as it is derived from that.  What is the caller, and how is
> this triggered?

FWIW the whole thread is available on lore:
https://lore.kernel.org/lkml/20200514061417.GA8367@lst.de/T/#t