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From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-kernel@vger.kernel.org,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Ingo Molnar <mingo@redhat.com>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH] uprobes: don't enable/disable signle step if the user did it
Date: Mon, 30 Jul 2012 16:36:58 +0530	[thread overview]
Message-ID: <20120730110658.GC11147@in.ibm.com> (raw)
In-Reply-To: <1343316043-13475-1-git-send-email-bigeasy@linutronix.de>

On Thu, Jul 26, 2012 at 05:20:43PM +0200, Sebastian Andrzej Siewior wrote:
> If someone is using single stepping over uprobe brackpoint then after
> we pass the uprobe single step, single stepping is disabled and the user
> who enebaled them in the first place does not know anything about this.
> 
> This patch avoids enabling / disabling the single step mode if it is
> already enabled.

This could happen any time 2 different entities call the
user_(en/dis)able_single_step() helpers on the same thread.

Wouldn't the right way to fix it be to teach these helpers
to honor what the TIF_SINGLESTEP flag setting was in the first place?
This way you'd get rid of the portability concerns too, since these
helpers are available on most architectures.

Ananth


  parent reply	other threads:[~2012-07-30 11:07 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-26 15:20 [PATCH] uprobes: don't enable/disable signle step if the user did it Sebastian Andrzej Siewior
2012-07-26 17:31 ` Oleg Nesterov
2012-07-27 17:39   ` Sebastian Andrzej Siewior
2012-07-27 18:04     ` Oleg Nesterov
2012-07-26 17:38 ` Sebastian Andrzej Siewior
2012-07-30 11:06 ` Ananth N Mavinakayanahalli [this message]
2012-07-30 14:16   ` Oleg Nesterov
2012-07-30 15:15     ` Sebastian Andrzej Siewior
2012-07-31  4:01     ` Ananth N Mavinakayanahalli
2012-07-31  5:22     ` Srikar Dronamraju
2012-07-31 17:38       ` Oleg Nesterov
2012-07-31 11:52     ` [PATCH 1/2] uprobes: Use a helper instead of ptrace's single step enable Sebastian Andrzej Siewior
2012-07-31 11:52       ` [PATCH 2/2] x86/uprobes: implement x86 specific arch_uprobe_*_step Sebastian Andrzej Siewior
2012-07-31 17:51         ` Oleg Nesterov
2012-07-31 19:30           ` Sebastian Andrzej Siewior
2012-08-01 12:26             ` Oleg Nesterov
2012-08-01 13:01               ` Q: user_enable_single_step() && update_debugctlmsr() Oleg Nesterov
2012-08-01 13:32                 ` Sebastian Andrzej Siewior
2012-08-01 13:46                   ` Oleg Nesterov
2012-08-01 13:54                     ` Sebastian Andrzej Siewior
2012-08-01 14:01                       ` Oleg Nesterov
2012-08-01 14:21                         ` Sebastian Andrzej Siewior
2012-08-01 14:31                           ` Oleg Nesterov
2012-08-01 14:47                             ` Oleg Nesterov
2012-08-01 14:51                             ` Sebastian Andrzej Siewior
2012-08-01 15:01                               ` Oleg Nesterov
2012-08-01 15:12                                 ` Sebastian Andrzej Siewior
2012-08-01 15:14                                   ` Oleg Nesterov
2012-08-01 18:46                                     ` Sebastian Andrzej Siewior
2012-08-02 13:05                                       ` Oleg Nesterov
2012-08-02 13:20                                         ` Sebastian Andrzej Siewior
2012-08-02 13:24                                           ` Oleg Nesterov
2012-08-01 13:43         ` [PATCH 2/2] x86/uprobes: implement x86 specific arch_uprobe_*_step Oleg Nesterov
2012-08-02  4:58           ` Ananth N Mavinakayanahalli
2012-07-31 17:40       ` [PATCH 1/2] uprobes: Use a helper instead of ptrace's single step enable Oleg Nesterov

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