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References: <20210217040958.1354670-1-ben.widawsky@intel.com>
 <20210217040958.1354670-5-ben.widawsky@intel.com> <YDBkOB3K8UqVakFf@Konrads-MacBook-Pro.local>
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In-Reply-To: <20210220163344.csczmkyxkpu4fxah@intel.com>
From:   Dan Williams <dan.j.williams@intel.com>
Date:   Sat, 20 Feb 2021 09:48:22 -0800
Message-ID: <CAPcyv4jWnW_i=jaGP_nXRuGgwmngObw_V8AOPY3k_YMHkL-8Eg@mail.gmail.com>
Subject: Re: [PATCH v5 4/9] cxl/mem: Add basic IOCTL interface
To:     Ben Widawsky <ben.widawsky@intel.com>
Cc:     Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        linux-cxl@vger.kernel.org, Linux ACPI <linux-acpi@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-nvdimm <linux-nvdimm@lists.01.org>,
        Linux PCI <linux-pci@vger.kernel.org>,
        Bjorn Helgaas <helgaas@kernel.org>,
        Chris Browy <cbrowy@avery-design.com>,
        Christoph Hellwig <hch@infradead.org>,
        David Hildenbrand <david@redhat.com>,
        David Rientjes <rientjes@google.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Jon Masters <jcm@jonmasters.org>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Rafael Wysocki <rafael.j.wysocki@intel.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Vishal Verma <vishal.l.verma@intel.com>,
        "John Groves (jgroves)" <jgroves@micron.com>,
        "Kelley, Sean V" <sean.v.kelley@intel.com>,
        kernel test robot <lkp@intel.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Al Viro <viro@zeniv.linux.org.uk>
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On Sat, Feb 20, 2021 at 8:33 AM Ben Widawsky <ben.widawsky@intel.com> wrote:
>
> On 21-02-19 20:22:00, Konrad Rzeszutek Wilk wrote:
> > ..snip..
> > > +static int handle_mailbox_cmd_from_user(struct cxl_mem *cxlm,
> > > +                                   const struct cxl_mem_command *cmd,
> > > +                                   u64 in_payload, u64 out_payload,
> > > +                                   s32 *size_out, u32 *retval)
> > > +{
> > > +   struct device *dev = &cxlm->pdev->dev;
> > > +   struct mbox_cmd mbox_cmd = {
> > > +           .opcode = cmd->opcode,
> > > +           .size_in = cmd->info.size_in,
> > > +           .size_out = cmd->info.size_out,
> > > +   };
> > > +   int rc;
> > > +
> > > +   if (cmd->info.size_out) {
> > > +           mbox_cmd.payload_out = kvzalloc(cmd->info.size_out, GFP_KERNEL);
> > > +           if (!mbox_cmd.payload_out)
> > > +                   return -ENOMEM;
> > > +   }
> > > +
> > > +   if (cmd->info.size_in) {
> > > +           mbox_cmd.payload_in = vmemdup_user(u64_to_user_ptr(in_payload),
> > > +                                              cmd->info.size_in);
> > > +           if (IS_ERR(mbox_cmd.payload_in))
> > > +                   return PTR_ERR(mbox_cmd.payload_in);
> >
> > Not that this should happen, but what if info.size_out was set? Should
> > you also free mbox_cmd.payload_out?
> >
>
> Thanks Konrad.
>
> Dan, do you want me to send a fixup patch? This bug was introduced from v4->v5.

Yes, please, incremental to libnvdimm-for-next which I'm planning to
send to Linus on Tuesday.