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 <20210401012722.527712-4-robdclark@gmail.com>
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From:   Doug Anderson <dianders@chromium.org>
Date:   Thu, 1 Apr 2021 08:34:50 -0700
Message-ID: <CAD=FV=XQoauA5kzmmj5ask_sK19mJycYLJfAOeriXsr2pvxaFw@mail.gmail.com>
Subject: Re: [PATCH v2 3/4] drm/msm: Fix debugfs deadlock
To:     Rob Clark <robdclark@gmail.com>
Cc:     dri-devel <dri-devel@lists.freedesktop.org>,
        Rob Clark <robdclark@chromium.org>,
        Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Jordan Crouse <jordan@cosmicpenguin.net>,
        "Kristian H. Kristensen" <hoegsberg@google.com>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <linux-arm-msm@vger.kernel.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <freedreno@lists.freedesktop.org>,
        open list <linux-kernel@vger.kernel.org>
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Hi,

On Wed, Mar 31, 2021 at 6:24 PM Rob Clark <robdclark@gmail.com> wrote:
>
> From: Rob Clark <robdclark@chromium.org>
>
> In normal cases the gem obj lock is acquired first before mm_lock.  The
> exception is iterating the various object lists.  In the shrinker path,
> deadlock is avoided by using msm_gem_trylock() and skipping over objects
> that cannot be locked.  But for debugfs the straightforward thing is to
> split things out into a separate list of all objects protected by it's
> own lock.
>
> Fixes: d984457b31c4 ("drm/msm: Add priv->mm_lock to protect active/inactive lists")
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> Tested-by: Douglas Anderson <dianders@chromium.org>

Reviewed-by: Douglas Anderson <dianders@chromium.org>