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Date:   Fri, 22 May 2020 22:26:09 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org,
        linux-sgx@vger.kernel.org, akpm@linux-foundation.org,
        dave.hansen@intel.com, nhorman@redhat.com, npmccallum@redhat.com,
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        tglx@linutronix.de, kai.svahn@intel.com, bp@alien8.de,
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        linux-security-module@vger.kernel.org,
        Suresh Siddha <suresh.b.siddha@intel.com>,
        Jethro Beekman <jethro@fortanix.com>,
        Haitao Huang <haitao.huang@linux.intel.com>,
        Chunyang Hui <sanqian.hcy@antfin.com>,
        Jordan Hand <jorhand@linux.microsoft.com>,
        Seth Moore <sethmo@google.com>
Subject: Re: [PATCH v30 10/20] x86/sgx: Linux Enclave Driver
Message-ID: <20200522192609.GE10319@linux.intel.com>
References: <20200515004410.723949-1-jarkko.sakkinen@linux.intel.com>
 <20200515004410.723949-11-jarkko.sakkinen@linux.intel.com>
 <20200521191236.GA23043@linux.intel.com>
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On Thu, May 21, 2020 at 12:12:36PM -0700, Sean Christopherson wrote:
> On Fri, May 15, 2020 at 03:44:00AM +0300, Jarkko Sakkinen wrote:
> > +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
> > +{
> > +	struct sgx_encl *encl = filep->private_data;
> > +	int ret, encl_flags;
> > +
> > +	encl_flags = atomic_fetch_or(SGX_ENCL_IOCTL, &encl->flags);
> > +	if (encl_flags & SGX_ENCL_IOCTL)
> > +		return -EBUSY;
> > +
> > +	if (encl_flags & SGX_ENCL_DEAD)
> > +		return -EFAULT;
> 
> Returning immediately is wrong as it leaves SGX_ENCL_IOCTL set.  This results
> in the application seeing -EBUSY on future ioctls() instead of -EFAULT.  Can be
> fixed as below.  Do you want me to send a formal patch on linux-sgx?

I just rewrote the same thing.

/Jarkko