Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20200617090247.1680188-1-shorne@gmail.com>
In-Reply-To: <20200617090247.1680188-1-shorne@gmail.com>
From:   Michel Lespinasse <walken@google.com>
Date:   Wed, 17 Jun 2020 05:04:52 -0700
Message-ID: <CANN689E_oP3T6J3Rw2rWv1KG3GO3JOJtCdCb3yMLz+u8hFN=Qw@mail.gmail.com>
Subject: Re: [PATCH] openrisc: Fix boot oops when DEBUG_VM is enabled
To:     Stafford Horne <shorne@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Jonas Bonn <jonas@southpole.se>,
        Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Steven Price <steven.price@arm.com>,
        Thomas Hellstrom <thellstrom@vmware.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
        openrisc@lists.librecores.org
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Jun 17, 2020 at 2:03 AM Stafford Horne <shorne@gmail.com> wrote:
> Since v5.8-rc1 OpenRISC Linux fails to boot when DEBUG_VM is enabled.
> This has been bisected to commit 42fc541404f2 ("mmap locking API: add
> mmap_assert_locked() and mmap_assert_write_locked()").
>
> The added locking checks exposed the issue that OpenRISC was not taking
> this mmap lock when during page walks for DMA operations.  This patch
> locks and unlocks the mmap lock for page walking.
>
> Fixes: 42fc541404f2 ("mmap locking API: add mmap_assert_locked() and mmap_assert_write_locked()"
> Cc: Michel Lespinasse <walken@google.com>
> Signed-off-by: Stafford Horne <shorne@gmail.com>

Thanks for the fix.

Reviewed-by: Michel Lespinasse <walken@google.com>