From: Will Deacon <will@kernel.org>
To: Will McVicker <willmcvicker@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Nick Desaulniers <ndesaulniers@google.com>,
linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
Andrei Vagin <avagin@gmail.com>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Nathan Chancellor <natechancellor@gmail.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
kernel-team@android.com, Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: Fix off-by-one vdso trampoline return value
Date: Thu, 12 Nov 2020 10:12:05 +0000 [thread overview]
Message-ID: <20201112101204.GA19506@willie-the-truck> (raw)
In-Reply-To: <20201112001422.340449-1-willmcvicker@google.com>
On Thu, Nov 12, 2020 at 12:14:22AM +0000, Will McVicker wrote:
> Depending on your host nm version, the generated header
> `include/generated/vdso32-offsets.h` may have the bottom bit set for the
> thumb vdso offset addresses (as observed when using llvm-nm). This
> results in an additional +1 for thumb vdso trampoline return values
> since compat_setup_return() already includes `vdso_trampoline + thumb`.
> As a result, I see a SIGBUS error when running the LTP test
> syscalls.rt_sigaction01. To fix this, let's clear the bottom bit of the
> vdso_offset in the VDSO_SYMBOL macro.
>
> Test: LTP test syscalls.rt_sigaction01
> Fixes: f01703b3d2e6 ("arm64: compat: Get sigreturn trampolines from vDSO")
> Signed-off-by: Will McVicker <willmcvicker@google.com>
> ---
> arch/arm64/include/asm/vdso.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/vdso.h b/arch/arm64/include/asm/vdso.h
> index f99dcb94b438..a7384379e8e1 100644
> --- a/arch/arm64/include/asm/vdso.h
> +++ b/arch/arm64/include/asm/vdso.h
> @@ -23,7 +23,7 @@
>
> #define VDSO_SYMBOL(base, name) \
> ({ \
> - (void *)(vdso_offset_##name - VDSO_LBASE + (unsigned long)(base)); \
> + (void *)((vdso_offset_##name & ~1UL) - VDSO_LBASE + (unsigned long)(base)); \
I don't think we need this in mainline, because the sigreturn trampoline
is just a bunch of .byte directives and I removed the sigreturn code from
the compat vdso in 2d071968a405 ("arm64: compat: Remove 32-bit sigreturn code
from the vDSO").
Might be needed in some stable kernels though (or we just backport the
patch I mentioned above)
Will
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-11-12 10:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 0:14 [PATCH] arm64: Fix off-by-one vdso trampoline return value Will McVicker
2020-11-12 1:00 ` Nick Desaulniers
2020-11-12 1:07 ` Nick Desaulniers
2020-11-12 2:14 ` Nick Desaulniers
2020-11-12 10:12 ` Will Deacon [this message]
2020-11-12 18:51 ` William Mcvicker
2020-11-16 22:55 ` William Mcvicker
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201112101204.GA19506@willie-the-truck \
--to=will@kernel.org \
--cc=0x7f454c46@gmail.com \
--cc=avagin@gmail.com \
--cc=catalin.marinas@arm.com \
--cc=clang-built-linux@googlegroups.com \
--cc=kernel-team@android.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=natechancellor@gmail.com \
--cc=ndesaulniers@google.com \
--cc=tglx@linutronix.de \
--cc=vincenzo.frascino@arm.com \
--cc=willmcvicker@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox