linux-kernel - Re: [PATCH v2 00/11] getting back -Wmaybe-uninitialized

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 11 Nov 2016 09:13:00 -0800
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Arnd Bergmann <arnd@...db.de>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        sayli karnik <karniksayli1995@...il.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Mark Brown <broonie@...nel.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Anna Schumaker <anna.schumaker@...app.com>,
        "David S. Miller" <davem@...emloft.net>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Ilya Dryomov <idryomov@...il.com>,
        Javier Martinez Canillas <javier@....samsung.com>,
        Jiri Kosina <jikos@...nel.org>,
        Ley Foon Tan <lftan@...era.com>,
        "Luis R . Rodriguez" <mcgrof@...nel.org>,
        Martin Schwidefsky <schwidefsky@...ibm.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Michal Marek <mmarek@...e.com>,
        Russell King <linux@...linux.org.uk>,
        Sean Young <sean@...s.org>,
        Sebastian Ott <sebott@...ux.vnet.ibm.com>,
        Trond Myklebust <trond.myklebust@...marydata.com>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        arcml <linux-snps-arc@...ts.infradead.org>,
        nios2-dev@...ts.rocketboards.org,
        linux-s390 <linux-s390@...r.kernel.org>,
        Linux Crypto Mailing List <linux-crypto@...r.kernel.org>,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        Linux NFS Mailing List <linux-nfs@...r.kernel.org>
Subject: Re: [PATCH v2 00/11] getting back -Wmaybe-uninitialized

On Thu, Nov 10, 2016 at 8:44 AM, Arnd Bergmann <arnd@...db.de> wrote:
>
> Please merge these directly if you are happy with the result.

I will take this.

I do see two warnings, but they both seem to be valid and recent,
though, so I have no issues with the spurious cases.

Warning #1:

  sound/soc/qcom/lpass-platform.c: In function ‘lpass_platform_pcmops_open’:
  sound/soc/qcom/lpass-platform.c:83:29: warning: ‘dma_ch’ may be used
uninitialized in this function [-Wmaybe-uninitialized]
    drvdata->substream[dma_ch] = substream;
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~

and 'dma_ch' usage there really is crazy and wrong. Broken by
022d00ee0b55 ("ASoC: lpass-platform: Fix broken pcm data usage")

Warning #2 is not a real bug, but it's reasonable that gcc doesn't
know that storage_bytes (chip->read_size) has to be 2/4. Again,
introduced recently by commit 231147ee77f3 ("iio: maxim_thermocouple:
Align 16 bit big endian value of raw reads"), so you didn't see it.

  drivers/iio/temperature/maxim_thermocouple.c: In function
‘maxim_thermocouple_read_raw’:
  drivers/iio/temperature/maxim_thermocouple.c:141:5: warning: ‘ret’
may be used uninitialized in this function [-Wmaybe-uninitialized]
    if (ret)
       ^
  drivers/iio/temperature/maxim_thermocouple.c:128:6: note: ‘ret’ was
declared here
    int ret;
        ^~~

and I guess that code can just initialize 'ret' to '-EINVAL' or
something to just make the theoretical "somehow we had a wrong
chip->read_size" case error out cleanly.

                Linus