Message-ID: <1ce4f09a-f4c3-ccd5-556e-3eb3aaa143f1@kernel.dk>
Date:   Sun, 22 Jan 2023 15:27:53 -0700
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Subject: Re: [PATCH v2] paride/pcd: return earlier when an error happens in
 pcd_atapi()
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To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     Tom Rix <trix@redhat.com>, tim@cyberelk.net, nathan@kernel.org,
        ndesaulniers@google.com, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev
References: <20230122154901.505142-1-trix@redhat.com>
 <1a501bc9-7058-6c47-0ebf-44459bc0e730@kernel.dk> <Y820PCtcJv12fJpI@ZenIV>
From:   Jens Axboe <axboe@kernel.dk>
In-Reply-To: <Y820PCtcJv12fJpI@ZenIV>
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On 1/22/23 3:10 PM, Al Viro wrote:
> On Sun, Jan 22, 2023 at 01:49:00PM -0700, Jens Axboe wrote:
>> On 1/22/23 8:49 AM, Tom Rix wrote:
>>> clang static analysis reports
>>> drivers/block/paride/pcd.c:856:36: warning: The left operand of '&'
>>>   is a garbage value [core.UndefinedBinaryOperatorResult]
>>>   tocentry->cdte_ctrl = buffer[5] & 0xf;
>>>                         ~~~~~~~~~ ^
>>
>> Has this one been compiled? I'm guessing not tested...
>>
>> In any case, this code is going away hopefully shortly, so let's not
>> bother with changes like this.
> 
> 	Look at the callers - the value left in entry is discarded if
> ->audio_ioctl(..., CDROMREADTOCENTRY, &entry) returns non-zero.  Sure,
> it's a nasal daemon territory, but realistically it's not going to be
> caught by testing.

I don't expect anyone really to be able to test it, but v1 had a pretty
basic issue that would've surely triggered a compiler warning had it
been compiled.

-- 
Jens Axboe