From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@elte.hu>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Anton Arapov <anton@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] uprobes: install_breakpoint() should fail if is_swbp_insn() == T
Date: Thu, 31 May 2012 18:24:11 +0530 [thread overview]
Message-ID: <20120531125411.GA24279@linux.vnet.ibm.com> (raw)
In-Reply-To: <1338466518.28384.57.camel@twins>
* Peter Zijlstra <peterz@infradead.org> [2012-05-31 14:15:18]:
> On Wed, 2012-05-30 at 19:49 +0200, Peter Zijlstra wrote:
> >
> > Oh, indeed. I overlooked copy_insn() is taking the page from the
> > page-cache instead of the page-tables and will thus get the original.
> >
>
> Related to this, what happens when we try to install a probe on a page
> that's already been COWed by a ptrace user?
>
> Say gdb did a code modification at or near the intended probe site.
>
If the page is already COWED because of an existing code modification
near the intended probe site, we are replacing it with another page
keeping the previous modification as is.
ptrace and uprobes tracing the same instruction wont work cleanly for
now.
--
thanks and regards
Srikar
next prev parent reply other threads:[~2012-05-31 12:56 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-30 16:57 [PATCH 0/3] uprobes: misc minor changes Oleg Nesterov
2012-05-30 16:58 ` [PATCH 1/3] uprobes: install_breakpoint() should fail if is_swbp_insn() == T Oleg Nesterov
2012-05-30 17:28 ` Peter Zijlstra
2012-05-30 17:37 ` Srikar Dronamraju
2012-05-30 17:49 ` Peter Zijlstra
2012-05-30 17:54 ` Peter Zijlstra
2012-05-30 18:03 ` Peter Zijlstra
2012-05-30 18:04 ` Srikar Dronamraju
2012-05-30 18:21 ` Peter Zijlstra
2012-05-31 18:53 ` Oleg Nesterov
2012-06-01 15:53 ` Oleg Nesterov
2012-06-01 16:33 ` Srikar Dronamraju
2012-06-01 17:20 ` Oleg Nesterov
2012-06-01 18:31 ` Oleg Nesterov
2012-06-02 18:21 ` Oleg Nesterov
2012-06-01 16:47 ` Srikar Dronamraju
2012-06-01 18:38 ` Oleg Nesterov
2012-05-31 12:15 ` Peter Zijlstra
2012-05-31 12:54 ` Srikar Dronamraju [this message]
2012-05-30 16:58 ` [PATCH 2/3] uprobes: remove the unnecessary initialization in add_utask() Oleg Nesterov
2012-05-30 16:58 ` [PATCH 3/3] uprobes: simplify the usage of uprobe->pending_list Oleg Nesterov
2012-05-30 17:48 ` Srikar Dronamraju
2012-05-30 18:10 ` Oleg Nesterov
2012-05-30 18:23 ` Srikar Dronamraju
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