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From: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: "Chang S. Bae" <chang.seok.bae@intel.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>, X86 ML <x86@kernel.org>,
	Len Brown <len.brown@intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	"H. J. Lu" <hjl.tools@gmail.com>,
	Dave Martin <Dave.Martin@arm.com>, Jann Horn <jannh@google.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Carlos O'Donell <carlos@redhat.com>,
	Tony Luck <tony.luck@intel.com>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	libc-alpha <libc-alpha@sourceware.org>,
	linux-arch <linux-arch@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 5/6] x86/signal: Detect and prevent an alternate signal stack overflow
Date: Fri, 26 Mar 2021 11:30:41 +0100	[thread overview]
Message-ID: <20210326103041.GB25229@zn.tnic> (raw)
In-Reply-To: <CALCETrXQZuvJQrHDMst6PPgtJxaS_sPk2JhwMiMDNPunq45YFg@mail.gmail.com>

On Thu, Mar 25, 2021 at 09:56:53PM -0700, Andy Lutomirski wrote:
> Nope.  on_sig_stack() is a horrible kludge and won't work here.  We
> could have something like __on_sig_stack() or sp_is_on_sig_stack() or
> something, though.

Yeah, see my other reply. Ack to either of those carved out helpers.

> I figure that the people whose programs spontaneously crash should get
> a hint why if they look at dmesg.  Maybe the message should say
> "overflowed sigaltstack -- try noavx512"?

I guess, as long as it is ratelimited. I mean, we can remove it later if
it starts gettin' annoying.

> We really ought to have a SIGSIGFAIL signal that's sent, double-fault
> style, when we fail to send a signal.

Yeap, we should be able to tell userspace that we couldn't send a
signal, hohumm.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2021-03-26 10:31 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-16  6:52 [PATCH v7 0/6] x86: Improve Minimum Alternate Stack Size Chang S. Bae
2021-03-16  6:52 ` [PATCH v7 1/6] uapi: Define the aux vector AT_MINSIGSTKSZ Chang S. Bae
2021-03-16  6:52   ` Chang S. Bae
2021-03-16  6:52 ` [PATCH v7 2/6] x86/signal: Introduce helpers to get the maximum signal frame size Chang S. Bae
2021-03-16  6:52 ` [PATCH v7 3/6] x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ Chang S. Bae
2021-03-16  6:52 ` [PATCH v7 4/6] selftest/sigaltstack: Use the AT_MINSIGSTKSZ aux vector if available Chang S. Bae
2021-03-16  6:52 ` [PATCH v7 5/6] x86/signal: Detect and prevent an alternate signal stack overflow Chang S. Bae
2021-03-16 11:52   ` Borislav Petkov
2021-03-16 18:26     ` Bae, Chang Seok
2021-03-25 16:20       ` Borislav Petkov
2021-03-25 17:21         ` Bae, Chang Seok
2021-03-25 20:14           ` Florian Weimer
2021-03-25 18:13   ` Andy Lutomirski
2021-03-25 18:54     ` Borislav Petkov
2021-03-25 21:11       ` Bae, Chang Seok
2021-03-25 21:27         ` Borislav Petkov
2021-03-26  4:56       ` Andy Lutomirski
2021-03-26 10:30         ` Borislav Petkov [this message]
2021-04-12 22:30           ` Bae, Chang Seok
2021-04-14 10:12             ` Borislav Petkov
2021-04-14 11:30               ` Florian Weimer
2021-04-14 12:06                 ` Borislav Petkov
2021-05-03  5:30                   ` Florian Weimer
2021-05-03 11:17                     ` Borislav Petkov
2021-03-26  4:58     ` Andy Lutomirski
2021-03-16  6:52 ` [PATCH v7 6/6] selftest/x86/signal: Include test cases for validating sigaltstack Chang S. Bae
2021-03-17 10:06 ` [PATCH v7 0/6] x86: Improve Minimum Alternate Stack Size Ingo Molnar
2021-03-17 10:44   ` Ingo Molnar
2021-03-19 18:12     ` Len Brown
2021-03-20 17:32       ` Ingo Molnar

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