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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     "Luck, Tony" <tony.luck@intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andreas Gruenbacher <agruenba@redhat.com>,
        Christoph Hellwig <hch@infradead.org>,
        "Darrick J. Wong" <djwong@kernel.org>, Jan Kara <jack@suse.cz>,
        Matthew Wilcox <willy@infradead.org>,
        cluster-devel <cluster-devel@redhat.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        ocfs2-devel@oss.oracle.com, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org
Subject: Re: [PATCH v7 05/19] iov_iter: Introduce fault_in_iov_iter_writeable
In-Reply-To: <YSvj/ML2saV3+5Ru@zeniv-ca.linux.org.uk>
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Date:   Sun, 29 Aug 2021 21:51:29 +0200
Message-ID: <87h7f8ghby.ffs@tglx>
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On Sun, Aug 29 2021 at 19:46, Al Viro wrote:

> On Sun, Aug 29, 2021 at 08:44:04PM +0200, Thomas Gleixner wrote:
>> On Sat, Aug 28 2021 at 22:51, Al Viro wrote:
>> > @@ -345,7 +346,7 @@ static inline int xsave_to_user_sigframe(struct xregs_state __user *buf)
>> >  	 */
>> >  	err = __clear_user(&buf->header, sizeof(buf->header));
>> >  	if (unlikely(err))
>> > -		return -EFAULT;
>> > +		return -X86_TRAP_PF;
>> 
>> This clear_user can be lifted into copy_fpstate_to_sigframe(). Something
>> like the below.
>
> Hmm...  This mixing of -X86_TRAP_... with -E... looks like it's asking for
> trouble in general.  Might be worth making e.g. fpu__restore_sig() (and
> its callers) return bool, seeing that we only check for 0/non-zero in
> there.

Let me fix that.