From: Nick Desaulniers <ndesaulniers@google.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
Will Deacon <will@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
"David S. Miller" <davem@davemloft.net>,
Paul Burton <paul.burton@mips.com>,
Sedat Dilek <sedat.dilek@gmail.com>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>
Subject: Re: [GIT PULL] compiler-attributes for v5.3-rc8
Date: Thu, 5 Sep 2019 10:18:41 -0700 [thread overview]
Message-ID: <CAKwvOdm3CbZ1Uad4b8+9HU8qDgTwSFw2oqjcAvFkR8jaQQN-5g@mail.gmail.com> (raw)
In-Reply-To: <CAHk-=wi2VOPoweqnDhxXKJ9fcLQzkV1oEDjteV=z-C7KXrpomg@mail.gmail.com>
On Thu, Sep 5, 2019 at 9:20 AM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> On Wed, Sep 4, 2019 at 11:18 AM Miguel Ojeda
> <miguel.ojeda.sandonis@gmail.com> wrote:
> >
> > I was going to send this for 5.4 since it is not that trivial, but since
> > you are doing an -rc8, and it fixes an oops, please consider pulling it.
>
> I looked at this, and while it seems safe, I end up worrying.
>
> Macro stringification isn't entirely obvious, and an unquoted string
> could become corrupted if the stringification ends up not happening
> immediately.
>
> It does seem safe just because we do
>
> #define __section(S) __attribute__((__section__(#S)))
>
> but I had to go _check_ that we do, because it wouldn't have been safe
> if there had been another level of macro expansion, because then the
> argument in turn could have been expanded before it was stringified.
>
> So sometimes you actually _want_ to pass in a string to be
> stringified, because it's safer. I realize it then gets string-quoted,
> but this has worked for gcc. Even if I suspect nobody really _thought_
> about it.
>
> So I'm not unhappy about the patch, but it's the kind of thing I'd
> really prefer not to do at this stage.
>
> Particularly since it seems to do other things too than just fix
> double quoting. As far as I can tell, it doesn't just fix double
> string quoting, it changes a lot of singly-quoted strings to use the
> macro and unquotes them, ie
>
> - __attribute__((__section__(".arch.info.init"))) = { \
> + __section(.arch.info.init) = { \
>
> doesn't actually "fix" anything that I can see, it just uses the simpler form.
Please consider picking up just:
https://github.com/ojeda/linux/commit/c97e82b97f4bba00304905fe7965f923abd2d755
That lone patch is the one that fixes the particularly observed Oops.
The rest are just cleanup; if I made that change in the more important
patch, why not clean up the rest of the instances in the kernel?
--
Thanks,
~Nick Desaulniers
next prev parent reply other threads:[~2019-09-05 17:18 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-04 18:18 [GIT PULL] compiler-attributes for v5.3-rc8 Miguel Ojeda
2019-09-05 6:23 ` Miguel Ojeda
2019-09-05 16:20 ` Linus Torvalds
2019-09-05 17:18 ` Nick Desaulniers [this message]
2019-09-05 17:22 ` Linus Torvalds
2019-09-05 19:53 ` Miguel Ojeda
2019-09-05 19:40 ` Miguel Ojeda
2019-09-05 20:53 ` Linus Torvalds
2019-09-06 20:11 ` Miguel Ojeda
2019-09-06 22:47 ` Nick Desaulniers
2019-09-06 23:11 ` Linus Torvalds
2019-09-07 0:06 ` Nick Desaulniers
2019-09-07 0:08 ` Linus Torvalds
2019-09-07 0:45 ` Nick Desaulniers
2019-09-07 0:58 ` Linus Torvalds
2019-09-07 7:52 ` Sedat Dilek
2019-09-07 11:59 ` Miguel Ojeda
2019-09-10 8:58 ` Sedat Dilek
2019-09-10 9:16 ` Miguel Ojeda
2019-09-08 13:19 Miguel Ojeda
2019-09-08 13:24 ` Miguel Ojeda
2019-09-08 17:25 ` pr-tracker-bot
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