From: Nathan Chancellor <nathan@kernel.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Guenter Roeck <linux@roeck-us.net>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Rich Felker <dalias@libc.org>, Arnd Bergmann <arnd@arndb.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Palmer Dabbelt <palmer@rivosinc.com>
Subject: Re: Linux 6.2-rc2
Date: Tue, 3 Jan 2023 11:26:37 -0700 [thread overview]
Message-ID: <Y7RzXSKYmAFAXMnr@dev-arch.thelio-3990X> (raw)
In-Reply-To: <CAMj1kXHqQoqoys83nEp=Q6oT68+-GpCuMjfnYK9pMy-X_+jjKw@mail.gmail.com>
On Tue, Jan 03, 2023 at 11:58:48AM +0100, Ard Biesheuvel wrote:
> On Tue, 3 Jan 2023 at 03:13, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > On Mon, Jan 2, 2023 at 5:45 PM Guenter Roeck <linux@roeck-us.net> wrote:
> > >
> > > ... and reverting commit 99cb0d917ff indeed fixes the problem.
> >
> > Hmm. My gut feel is that this just exposes some bug in binutils.
> >
> > That said, maybe that commit should not have added its own /DISCARDS/
> > thing, and instead just added that "*(.note.GNU-stack)" to the general
> > /DISCARDS/ thing that is defined by the
> >
> > #define DISCARDS ..
> >
> > a little bit later, so that we only end up with one single DISCARD
> > list. Something like this (broken patch on purpose):
> >
> > --- a/include/asm-generic/vmlinux.lds.h
> > +++ b/include/asm-generic/vmlinux.lds.h
> > @@ -897,5 +897,4 @@
> > */
> > #define NOTES \
> > - /DISCARD/ : { *(.note.GNU-stack) } \
> > .notes : AT(ADDR(.notes) - LOAD_OFFSET) { \
> > BOUNDED_SECTION_BY(.note.*, _notes) \
> > @@ -1016,4 +1015,5 @@
> > #define DISCARDS \
> > /DISCARD/ : { \
> > + *(.note.GNU-stack) \
> > EXIT_DISCARDS \
> > EXIT_CALL \
> >
> > But maybe that DISCARDS macrop ends up being used too late?
> >
>
> Masahiro's v1 did something like this, and it caused an issue on
> RISC-V, which is why we ended up with this approach instead.
>
> > It really shouldn't matter, but here we are, with a build problem with
> > some random old binutils on an odd platform..
> >
>
> AIUI, the way ld.bfd used to combine output sections may also affect
> the /DISCARD/ pseudo-section, and so introducing it much earlier
> results in these discards to be interpreted in a different order.
>
> The purpose of this change is to prevent .note.GNU-stack from deciding
> the section type of the .notes output section, and so keeping it in
> its own section should be sufficient. E.g.,
This appears to work for me. It fixes the build failures that
ClangBuiltLinux's CI reported and I still see a build ID for arm64's
vmlinux:
Tested-by: Nathan Chancellor <nathan@kernel.org>
I will throw this into the ClangBuiltLinux CI to make sure there are no
additional surprises but I do not expect to find anything.
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -896,7 +896,7 @@
> * Otherwise, the type of .notes section would become PROGBITS
> instead of NOTES.
> */
> #define NOTES \
> - /DISCARD/ : { *(.note.GNU-stack) } \
> + .note.GNU-stack : { *(.note.GNU-stack) } \
> .notes : AT(ADDR(.notes) - LOAD_OFFSET) { \
> BOUNDED_SECTION_BY(.note.*, _notes) \
> } NOTES_HEADERS \
>
> The .note.GNU-stack has zero size, so the result should be the same.
next prev parent reply other threads:[~2023-01-03 18:27 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-01 22:01 Linux 6.2-rc2 Linus Torvalds
2023-01-02 10:20 ` Build regressions/improvements in v6.2-rc2 Geert Uytterhoeven
2023-01-02 22:56 ` Linux 6.2-rc2 Guenter Roeck
2023-01-03 0:21 ` Linus Torvalds
2023-01-03 1:45 ` Guenter Roeck
2023-01-03 2:13 ` Linus Torvalds
2023-01-03 3:57 ` Guenter Roeck
2023-01-03 4:26 ` Nathan Chancellor
2023-01-03 9:14 ` Thorsten Leemhuis
2023-01-03 10:58 ` Ard Biesheuvel
2023-01-03 11:45 ` Conor Dooley
2023-01-03 12:22 ` Guenter Roeck
2023-01-03 18:26 ` Nathan Chancellor [this message]
2023-01-03 18:34 ` Linus Torvalds
2023-01-05 13:44 ` Masahiro Yamada
2023-01-04 10:34 ` Michael Ellerman
2023-01-10 0:32 ` SeongJae Park
2023-01-10 18:39 ` Masahiro Yamada
2023-01-10 19:14 ` SeongJae Park
2023-01-23 9:09 ` Masahiro Yamada
2023-01-23 18:27 ` SeongJae Park
2023-02-06 22:56 ` SeongJae Park
2023-02-08 1:27 ` Masahiro Yamada
2023-01-13 14:59 ` Tom Saeger
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