From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl,
mingo@redhat.com, srikar@linux.vnet.ibm.com,
roland@hack.frob.com
Subject: Re: [PATCH 2/2] x86/uprobes: implement x86 specific arch_uprobe_*_step
Date: Thu, 2 Aug 2012 10:28:31 +0530 [thread overview]
Message-ID: <20120802045831.GA8538@in.ibm.com> (raw)
In-Reply-To: <20120801134337.GA3923@redhat.com>
On Wed, Aug 01, 2012 at 03:43:37PM +0200, Oleg Nesterov wrote:
...
> However, I am not sure we can trust it. We are in kernel mode,
> DEBUGCTLMSR_BTF can be cleared by kprobes (Ananth, please correct me).
> I think we need to check TIF_BLOCKSTEP.
Kprobes resets DEBUGCTLMSR_BTF only if we have to single-step in
hardware. It puts the flag back if TIF_BLOCKSTEP is set, after the
single-step is complete; so yes, a better check is TIF_BLOCKSTEP.
Ananth
next prev parent reply other threads:[~2012-08-02 4:58 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
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 [this message]
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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