From: Al Viro <viro@ZenIV.linux.org.uk>
To: Rob Clark <robdclark@gmail.com>
Cc: Vaishali Thakkar <vaishali.thakkar@oracle.com>,
David Airlie <airlied@linux.ie>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
freedreno@lists.freedesktop.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Julia Lawall <julia.lawall@lip6.fr>
Subject: Re: Use of copy_from_user in msm_gem_submit.c while holding a spin_lock
Date: Wed, 17 Aug 2016 20:31:20 +0100 [thread overview]
Message-ID: <20160817193120.GG2356@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CAF6AEGv+0y14UXraXQkN+rRB-5-i=1Vr-0QtZ5DNzErXnqriug@mail.gmail.com>
On Wed, Aug 17, 2016 at 03:24:38PM -0400, Rob Clark wrote:
> hmm, looks like, at least on arm (not sure about arm64),
>
> #define __copy_from_user_inatomic __copy_from_user
>
> ie. copy_from_user() minus the access_ok() and memset in the
> !access_ok() path.. but maybe what I want is just the
> pagefault_disable() if that disables copy_from_user() being able to
> block..
On a bunch of platforms copy_from_user() starts with might_sleep(); again,
that'll spread to all of the pretty soon.
Right now those primitives are very badly out of sync; this will change,
but let's not add more PITA sources.
next prev parent reply other threads:[~2016-08-17 19:31 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-17 11:40 Use of copy_from_user in msm_gem_submit.c while holding a spin_lock Vaishali Thakkar
2016-08-17 15:08 ` Rob Clark
2016-08-17 17:08 ` Al Viro
2016-08-17 18:49 ` Rob Clark
2016-08-17 18:58 ` Rob Clark
2016-08-17 19:15 ` Al Viro
2016-08-17 19:24 ` Rob Clark
2016-08-17 19:31 ` Al Viro [this message]
2016-08-18 8:31 ` Daniel Vetter
2016-08-17 21:29 ` Rob Clark
2016-08-18 8:36 ` Daniel Vetter
2016-08-18 10:55 ` Rob Clark
2016-08-18 13:08 ` Daniel Vetter
2016-08-18 13:14 ` Rob Clark
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