From: Carlos O'Donell <codonell@redhat.com>
To: Florian Weimer <fweimer@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Paul Burton <paul.burton@mips.com>,
Will Deacon <will.deacon@arm.com>,
Boqun Feng <boqun.feng@gmail.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Russell King <linux@armlinux.org.uk>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>, carlos <carlos@redhat.com>,
Joseph Myers <joseph@codesourcery.com>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
libc-alpha <libc-alpha@sourceware.org>,
Thomas Gleixner <tglx@linutronix.de>, Ben Maurer <bmaurer@fb.com>,
Peter Zijlstra <peterz@infradead.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
Rich Felker <dalias@libc.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-api <linux-api@vger.kernel.org>
Subject: Re: [PATCH 1/4] glibc: Perform rseq(2) registration at C startup and thread creation (v7)
Date: Fri, 05 Apr 2019 15:40:00 -0000 [thread overview]
Message-ID: <43f97ddb-c8df-27ea-9517-63252ebd3183@redhat.com> (raw)
In-Reply-To: <87y34o4xt3.fsf@oldenburg2.str.redhat.com>
On 4/5/19 5:16 AM, Florian Weimer wrote:
> * Carlos O'Donell:
>> It is valuable that it be a trap, particularly for constant pools because
>> it means that a jump into the constant pool will trap.
>
> Sorry, I don't understand why this matters in this context. Would you
> please elaborate?
Sorry, I wasn't very clear.
My point is only that any accidental jumps, either with off-by-one (like you
fixed in gcc/glibc's signal unwinding most recently), result in a process fault
rather than executing RSEQ_SIG as a valid instruction *and then* continuing
onwards to the handler.
A process fault is achieved either by a trap, or an invalid instruction, or
a privileged insn (like suggested for MIPS in this thread).
--
Cheers,
Carlos.
next prev parent reply other threads:[~2019-04-05 15:40 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-12 19:43 [PATCH 0/4] Restartable Sequences support for glibc 2.30 Mathieu Desnoyers
2019-02-12 19:43 ` [PATCH 1/4] glibc: Perform rseq(2) registration at C startup and thread creation (v7) Mathieu Desnoyers
2019-03-22 20:09 ` Carlos O'Donell
2019-03-25 15:54 ` Mathieu Desnoyers
2019-03-27 9:16 ` Martin Schwidefsky
2019-03-27 20:01 ` Mathieu Desnoyers
2019-03-27 20:38 ` Carlos O'Donell
2019-03-28 7:50 ` Martin Schwidefsky
2019-03-28 15:43 ` Mathieu Desnoyers
2019-04-02 6:02 ` Michael Ellerman
2019-04-02 7:08 ` Florian Weimer
2019-04-04 20:33 ` Carlos O'Donell
2019-04-05 9:16 ` Florian Weimer
2019-04-05 15:40 ` Carlos O'Donell [this message]
2019-04-08 21:45 ` Tulio Magno Quites Machado Filho
2019-04-08 22:06 ` Carlos O'Donell
2019-04-09 4:28 ` Michael Ellerman
2019-04-09 9:52 ` Alan Modra
2019-04-09 14:13 ` Tulio Magno Quites Machado Filho
2019-04-09 14:58 ` Carlos O'Donell
2019-04-09 15:58 ` Mathieu Desnoyers
2019-04-18 15:33 ` Mathieu Desnoyers
2019-04-09 16:34 ` Mathieu Desnoyers
2019-04-04 20:16 ` Carlos O'Donell
2019-04-04 20:50 ` Carlos O'Donell
[not found] ` <20190404214151.6ogrm34dok52az4h@pburton-laptop>
2019-04-09 17:24 ` Mathieu Desnoyers
2019-04-18 22:42 ` Mathieu Desnoyers
2019-04-24 15:28 ` Mathieu Desnoyers
[not found] ` <20190424231303.zu2irxd5g3v7yqey@pburton-laptop>
2019-04-25 1:57 ` Maciej W. Rozycki
2019-02-12 19:43 ` [PATCH 2/4] glibc: sched_getcpu(): use rseq cpu_id TLS on Linux Mathieu Desnoyers
2019-03-22 20:14 ` Carlos O'Donell
2019-02-12 19:43 ` [PATCH 3/4] support record failure: allow use from constructor Mathieu Desnoyers
2019-03-22 20:30 ` Carlos O'Donell
2019-02-12 19:51 ` [PATCH 4/4] rseq registration tests (v2) Mathieu Desnoyers
2019-03-27 21:21 ` Carlos O'Donell
2019-04-04 20:04 ` Mathieu Desnoyers
2019-04-04 20:11 ` Carlos O'Donell
2019-04-04 20:23 ` Mathieu Desnoyers
2019-04-05 10:01 ` Florian Weimer
2019-04-05 13:50 ` Carlos O'Donell
2019-04-05 15:27 ` Florian Weimer
2019-04-05 17:38 ` Carlos O'Donell
2019-04-05 19:43 ` Florian Weimer
2019-04-08 22:07 ` Carlos O'Donell
2019-03-22 17:34 ` [PATCH 0/4] Restartable Sequences support for glibc 2.30 Carlos O'Donell
2019-03-22 17:55 ` Mathieu Desnoyers
2019-03-22 18:04 ` Carlos O'Donell
2019-03-22 17:39 ` Florian Weimer
2019-03-22 17:47 ` Carlos O'Donell
2019-03-22 17:51 ` Florian Weimer
2019-03-22 19:46 ` Carlos O'Donell
2019-03-22 20:14 ` Mathieu Desnoyers
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