From: "Paul E. McKenney" <paulmck@kernel.org>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Josh Triplett <josh@joshtriplett.org>,
Kees Cook <keescook@chromium.org>,
LKML <linux-kernel@vger.kernel.org>,
rcu@vger.kernel.org,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH v2] srcu: avoid escaped section names
Date: Wed, 7 Oct 2020 14:05:03 -0700 [thread overview]
Message-ID: <20201007210503.GR29330@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <20201006065623.GA2418984@ubuntu-m3-large-x86>
On Mon, Oct 05, 2020 at 11:56:23PM -0700, Nathan Chancellor wrote:
> On Mon, Oct 05, 2020 at 11:49:10AM -0700, Paul E. McKenney wrote:
> > On Mon, Oct 05, 2020 at 08:38:42PM +0200, Sedat Dilek wrote:
> > > On Mon, Oct 5, 2020 at 8:29 PM 'Nick Desaulniers' via Clang Built
> > > Linux <clang-built-linux@googlegroups.com> wrote:
> > > >
> > > > On Fri, Oct 2, 2020 at 1:51 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> > > > >
> > > > > On Wed, Sep 30, 2020 at 01:55:48PM -0700, Nick Desaulniers wrote:
> > > > > > On Wed, Sep 30, 2020 at 1:40 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> > > > > > >
> > > > > > > On Tue, Sep 29, 2020 at 12:25:49PM -0700, Nick Desaulniers wrote:
> > > > > > > > The stringification operator, `#`, in the preprocessor escapes strings.
> > > > > > > > For example, `# "foo"` becomes `"\"foo\""`. GCC and Clang differ in how
> > > > > > > > they treat section names that contain \".
> > > > > > > >
> > > > > > > > The portable solution is to not use a string literal with the
> > > > > > > > preprocessor stringification operator.
> > > > > > > >
> > > > > > > > Link: https://bugs.llvm.org/show_bug.cgi?id=42950
> > > > > > > > Fixes: commit fe15b50cdeee ("srcu: Allocate per-CPU data for DEFINE_SRCU() in modules")
> > > > > > > > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> > > > > > >
> > > > > > > I am guessing that this needs to go up with other patches. If so:
> > > > > > >
> > > > > > > Acked-by: Paul E. McKenney <paulmck@kernel.org>
> > > > > > >
> > > > > > > If not, let me know and I will queue it.
> > > > > >
> > > > > > I could have bundled them up as a series. I think you can pick it up,
> > > > > > and I'll owe you a beer?
> > > > >
> > > > > It is queued, thank you!
> > > > >
> > > > > When does it need to hit mainline? (Your default is the v5.11 merge
> > > > > window, that is, the one following the upcoming merge window.)
> > > >
> > > > No rush, this patch wasn't blocking any known issue, just a cleanup
> > > > while I was in the neighborhood. 100 years ago, I was an Eagle scout.
> > > > Pretty sure there was a motto about "leaving things better than you
> > > > found them." Thanks for help resolving the merge conflict reported in
> > > > -next related to it.
> > >
> > > Wasn't there a problem with your "Fixes:" tag (Fixes: *drop word
> > > "commit"* commit_hashid ("...")?
> >
> > Indeed there was, and I have it noted to be fixed on my next rebase.
> >
> > Perhaps another reason not to rush to mainline though. ;-)
> >
> > Thanx, Paul
>
> I am replying here as well so that the relevant parties are in the know
> but I believe this patch should be fast tracked with a cc stable tag as
> this appears to be the root cause of the issue that Nick reported a few
> weeks ago:
>
> https://lore.kernel.org/rcu/CAKwvOdm4AQhobdkKT08bjPGb15N58QN79XWxEaQt-P5Dk4+avQ@mail.gmail.com/
> https://github.com/ClangBuiltLinux/linux/issues/1081
>
> I can reproduce the issue on next-20201002 on my Raspberry Pi 4 just by
> booting it up. As soon as I apply this patch, all warnings disappear. I
> asked the original reporters to test if the patch resolves the issue for
> them but I figured more visibility on this, the sooner. The commit
> message might need to be revised if this turns out to be the case to
> make it more apparent that it has a user visible issue, rather than just
> a QoL fix.
>
> Additionally, it seems like the patch is missing some reviewed by tags
> from Kees, Sedat, and myself. Feel free to add a
>
> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
>
> as well.
Good catch, and apologies to all concerned! I have removed the stray
"commit" and, based posts earlier in this thread, I have also added:
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Thank you all!
Thanx, Paul
prev parent reply other threads:[~2020-10-07 21:05 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 19:22 [PATCH] srcu: avoid escaped section names Nick Desaulniers
2020-09-29 19:22 ` Nick Desaulniers
2020-09-29 19:25 ` [PATCH v2] " Nick Desaulniers
2020-09-29 23:45 ` Kees Cook
2020-09-30 16:27 ` Nathan Chancellor
2020-09-30 16:41 ` Sedat Dilek
2020-09-30 18:57 ` Joe Perches
2020-09-30 19:16 ` [RFC PATCH next-20200930] treewide: Convert macro and uses of __section(foo) to __section("foo") Joe Perches
2020-09-30 21:40 ` Nick Desaulniers
2020-09-30 22:06 ` Joe Perches
2020-09-30 22:12 ` Joe Perches
2020-09-30 22:20 ` Nick Desaulniers
2020-09-30 22:25 ` Joe Perches
2020-09-30 22:56 ` Joe Perches
2020-10-01 10:15 ` Miguel Ojeda
2020-10-01 19:05 ` Joe Perches
2020-10-01 19:39 ` Segher Boessenkool
2020-10-01 20:19 ` Joe Perches
2020-10-05 18:36 ` Nick Desaulniers
2020-10-05 18:46 ` Joe Perches
2020-10-06 0:34 ` Joel Stanley
2020-10-06 3:22 ` Joe Perches
2020-09-30 20:40 ` [PATCH v2] srcu: avoid escaped section names Paul E. McKenney
2020-09-30 20:55 ` Nick Desaulniers
2020-10-02 20:51 ` Paul E. McKenney
2020-10-05 18:29 ` Nick Desaulniers
2020-10-05 18:38 ` Sedat Dilek
2020-10-05 18:49 ` Paul E. McKenney
2020-10-06 6:56 ` Nathan Chancellor
2020-10-07 21:05 ` Paul E. McKenney [this message]
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