Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Sun, 16 May 2021 14:17:14 +0100
From:   Khaled Romdhani <khaledromdhani216@gmail.com>
To:     Colin Ian King <colin.king@canonical.com>,
        Borislav Petkov <bp@alien8.de>
Cc:     peterz@infradead.org, jpoimboe@redhat.com, jbaron@akamai.com,
        rostedt@goodmis.org, ardb@kernel.org, tglx@linutronix.de,
        mingo@redhat.com, x86@kernel.org, hpa@zytor.com,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH-next] x86/kernel: Fix unchecked return value
Message-ID: <20210516131714.GB32445@ard0534>
References: <20210515202212.24836-1-khaledromdhani216@gmail.com>
 <YKAw3Yl8c6nU1zng@zn.tnic>
 <6f149c2e-eeb0-6b50-2b54-a56ae4646ea5@canonical.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <6f149c2e-eeb0-6b50-2b54-a56ae4646ea5@canonical.com>
User-Agent: Mutt/1.9.4 (2018-02-28)
Precedence: bulk

On Sat, May 15, 2021 at 09:51:23PM +0100, Colin Ian King wrote:
> On 15/05/2021 21:36, Borislav Petkov wrote:
> > On Sat, May 15, 2021 at 09:22:12PM +0100, Khaled ROMDHANI wrote:
> >> From the coverity scan analysis, the return value from
> >> insn_decode_kernel is not checked. It is a macro constructed
> >> from the insn_decode function which may fail and return
> >> negative integer. Fix this by explicitly checking the
> >> return value.
> >>
> >> Addresses-Coverity: ("Unchecked return value")
> >> Signed-off-by: Khaled ROMDHANI <khaledromdhani216@gmail.com>
> >> ---
> >>  arch/x86/kernel/jump_label.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
> >> index a762dc1c615e..bf0ea003b6e7 100644
> >> --- a/arch/x86/kernel/jump_label.c
> >> +++ b/arch/x86/kernel/jump_label.c
> >> @@ -23,7 +23,7 @@ int arch_jump_entry_size(struct jump_entry *entry)
> >>  {
> >>  	struct insn insn = {};
> >>  
> >> -	insn_decode_kernel(&insn, (void *)jump_entry_code(entry));
> >> +	WARN_ON(insn_decode_kernel(&insn, (void *)jump_entry_code(entry)));
> > 
> > I don't think coverity is smart enough to notice...
> > 
> >>  	BUG_ON(insn.length != 2 && insn.length != 5);
> > 	^^^^^^^^^^^^^
> > 
> > ... this line.
> > 
> > 
> Indeed. One needs to be careful with false positives with Coverity.
> 
> Colin

Yes. I shall be.

Thanks,

Khaled.