From: Thomas Gleixner <tglx@linutronix.de>
To: "Chang S. Bae" <chang.seok.bae@intel.com>,
bp@suse.de, mingo@kernel.org, luto@kernel.org, x86@kernel.org
Cc: len.brown@intel.com, dave.hansen@intel.com, hjl.tools@gmail.com,
Dave.Martin@arm.com, jannh@google.com, mpe@ellerman.id.au,
carlos@redhat.com, tony.luck@intel.com, ravi.v.shankar@intel.com,
libc-alpha@sourceware.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
chang.seok.bae@intel.com
Subject: Re: [PATCH v9 0/6] Improve Minimum Alternate Stack Size
Date: Wed, 19 May 2021 11:25:06 +0200 [thread overview]
Message-ID: <87sg2jcbyl.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20210518200320.17239-1-chang.seok.bae@intel.com>
On Tue, May 18 2021 at 13:03, Chang S. Bae wrote:
> During signal entry, the kernel pushes data onto the normal userspace
> stack. On x86, the data pushed onto the user stack includes XSAVE state,
> which has grown over time as new features and larger registers have been
> added to the architecture.
>
> MINSIGSTKSZ is a constant provided in the kernel signal.h headers and
> typically distributed in lib-dev(el) packages, e.g. [1]. Its value is
> compiled into programs and is part of the user/kernel ABI. The MINSIGSTKSZ
> constant indicates to userspace how much data the kernel expects to push on
> the user stack, [2][3].
>
> However, this constant is much too small and does not reflect recent
> additions to the architecture. For instance, when AVX-512 states are in
> use, the signal frame size can be 3.5KB while MINSIGSTKSZ remains 2KB.
>
> The bug report [4] explains this as an ABI issue. The small MINSIGSTKSZ can
> cause user stack overflow when delivering a signal.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
prev parent reply other threads:[~2021-05-19 9:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-18 20:03 [PATCH v9 0/6] Improve Minimum Alternate Stack Size Chang S. Bae
2021-05-18 20:03 ` [PATCH v9 1/6] uapi: Define the aux vector AT_MINSIGSTKSZ Chang S. Bae
2021-05-19 14:19 ` [tip: x86/fpu] uapi/auxvec: " tip-bot2 for Chang S. Bae
2021-05-18 20:03 ` [PATCH v9 2/6] x86/signal: Introduce helpers to get the maximum signal frame size Chang S. Bae
2021-05-19 14:19 ` [tip: x86/fpu] " tip-bot2 for Chang S. Bae
2021-05-18 20:03 ` [PATCH v9 3/6] x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ Chang S. Bae
2021-05-19 14:19 ` [tip: x86/fpu] " tip-bot2 for Chang S. Bae
2021-05-18 20:03 ` [PATCH v9 4/6] selftest/sigaltstack: Use the AT_MINSIGSTKSZ aux vector if available Chang S. Bae
2021-05-19 14:19 ` [tip: x86/fpu] " tip-bot2 for Chang S. Bae
2021-05-18 20:03 ` [PATCH v9 5/6] x86/signal: Detect and prevent an alternate signal stack overflow Chang S. Bae
2021-05-19 14:19 ` [tip: x86/fpu] " tip-bot2 for Chang S. Bae
2021-05-18 20:03 ` [PATCH v9 6/6] selftest/x86/signal: Include test cases for validating sigaltstack Chang S. Bae
2021-05-19 14:19 ` [tip: x86/fpu] " tip-bot2 for Chang S. Bae
2021-05-19 9:25 ` Thomas Gleixner [this message]
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