From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Will Deacon <will.deacon@arm.com>
Cc: Simon Marchi <simon.marchi@ericsson.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: Possible race between PTRACE_SETVFPREGS and PTRACE_CONT on ARM?
Date: Tue, 31 May 2016 15:18:17 +0100 [thread overview]
Message-ID: <20160531141817.GW19428@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20160531135251.GK24936@arm.com>
On Tue, May 31, 2016 at 02:52:52PM +0100, Will Deacon wrote:
> The only thing I'm uncertain of is whether or not PTRACE_SEIZE/PTRACE_LISTEN
> allow switching to the child (but even then, how is the parent doing
> to issue such a request?).
I can't see how that would be possible - the parent needs to finish
the vfp_set() call before it can issue any others - and there can
only be one tracer. IOW, if we're in vfp_set(), the thread must
have attached to the child, at which point PTRACE_SEIZE will be
rejected.
PTRACE_LISTEN also requires the child to be in STOP state as well, and
again, can only be issued from the current tracer.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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next prev parent reply other threads:[~2016-05-31 14:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-30 17:48 Possible race between PTRACE_SETVFPREGS and PTRACE_CONT on ARM? Simon Marchi
2016-05-30 21:35 ` Russell King - ARM Linux
2016-05-30 22:40 ` Russell King - ARM Linux
2016-05-31 13:52 ` Will Deacon
2016-05-31 14:18 ` Russell King - ARM Linux [this message]
2016-06-01 12:54 ` Simon Marchi
2016-06-02 13:15 ` Russell King - ARM Linux
2016-06-02 13:17 ` Simon Marchi
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