From: David Vernet <void@manifault.com>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org,
Nathan Chancellor <nathan@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Miguel Ojeda <ojeda@kernel.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Josh Poimboeuf <jpoimboe@kernel.org>,
x86@kernel.org, Linus Torvalds <torvalds@linux-foundation.org>,
clang-built-linux <llvm@lists.linux.dev>
Subject: Re: [tip: objtool/core] start_kernel: Add __no_stack_protector function attribute
Date: Fri, 19 May 2023 12:42:15 -0500 [thread overview]
Message-ID: <20230519174215.GA2158284@maniforge> (raw)
In-Reply-To: <CAKwvOd=ywPnLS40HNUnXH1nqm3Ke3sMtomSgL+rVOoSjXvQB=A@mail.gmail.com>
On Fri, May 19, 2023 at 10:18:40AM -0700, Nick Desaulniers wrote:
> On Fri, May 19, 2023 at 10:11 AM David Vernet <void@manifault.com> wrote:
> >
> > On Thu, May 18, 2023 at 11:08:03AM -0000, tip-bot2 for ndesaulniers@google.com wrote:
> > > The following commit has been merged into the objtool/core branch of tip:
> > >
> > > Commit-ID: 514ca14ed5444b911de59ed3381dfd195d99fe4b
> > > Gitweb: https://git.kernel.org/tip/514ca14ed5444b911de59ed3381dfd195d99fe4b
> > > Author: ndesaulniers@google.com <ndesaulniers@google.com>
> > > AuthorDate: Mon, 17 Apr 2023 15:00:05 -07:00
> > > Committer: Josh Poimboeuf <jpoimboe@kernel.org>
> >
> > Hi Nick, Josh, Peter,
> >
> > Do you have an ETA for when this will make its way to Linus' tree?
> > clang-17 built kernels have failed to boot since [0], so it would be
> > nice to get this in sooner rather than later if possible.
>
> David,
> Can you confirm that your version of clang-17 is updated? clang-17 is
> unreleased; ToT will become clang-17.
>
> https://reviews.llvm.org/rGfc4494dffa5422b2be5442c235554e76bed79c8a
> should have fixed any boot failures related to stack protectors. That
> is to say that Josh's series is irrelevant to anyone using either an
> existing release of clang, or something closer to ToT than April 13.
Thanks for the quick reply, Nick. The latest clang-17 does indeed fix
the issue. Apologies for not trying that first -- I was using the only
tagged verson of clang-17 (which admittedly is not a released version),
and figured it wasn't a compiler bug given that the assembly looked
sane, compilers are allowed to do all sorts of interesting things with
__noreturn, and that [1] removes -fstack-protector from start_kernel()
altogether.
[1]: https://lore.kernel.org/lkml/20230412-no_stackp-v1-1-46a69b507a4b@google.com/
> LLVM commit fc4494dffa54 ("[StackProtector] don't check stack
> protector before calling nounwind functions")
> landed April 13, so please check that your build of clang-17 is after that date.
>
> Either way, thanks for testing with clang, and the report. You can
> always file a bug at our issue tracker:
> https://github.com/ClangBuiltLinux/linux/issues or see our page for
> more ways to get in touch:
> https://clangbuiltlinux.github.io/
> We're very active on our mailing list, and on IRC.
Ack, thanks for letting me know for next time.
- David
next prev parent reply other threads:[~2023-05-19 17:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-17 22:00 [PATCH v2 0/2] start_kernel: omit stack canary ndesaulniers
2023-04-17 22:00 ` [PATCH v2 1/2] start_kernel: add no_stack_protector fn attr ndesaulniers
2023-05-18 11:08 ` [tip: objtool/core] start_kernel: Add __no_stack_protector function attribute tip-bot2 for ndesaulniers@google.com
2023-05-19 17:11 ` David Vernet
2023-05-19 17:18 ` Nick Desaulniers
2023-05-19 17:42 ` David Vernet [this message]
2023-04-17 22:00 ` [PATCH v2 2/2] start_kernel: omit prevent_tail_call_optimization for newer toolchains ndesaulniers
2023-05-18 11:08 ` [tip: objtool/core] start_kernel: Omit prevent_tail_call_optimization() " tip-bot2 for ndesaulniers@google.com
2023-04-18 21:38 ` [PATCH v2 0/2] start_kernel: omit stack canary Josh Poimboeuf
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