From: Oleg Nesterov <oleg@redhat.com>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
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: Fri, 1 Jun 2012 20:38:44 +0200 [thread overview]
Message-ID: <20120601183844.GB31771@redhat.com> (raw)
In-Reply-To: <20120601164725.GK24279@linux.vnet.ibm.com>
On 06/01, Srikar Dronamraju wrote:
>
> * Oleg Nesterov <oleg@redhat.com> [2012-05-31 20:53:39]:
>
> > __find_next_vma_info() checks tmpvi->mm == vma->vm_mm to detect the
> > already visited mm/vma. However, afaics this can be false positive?
> >
> > The caller, register_for_each_vma(), does mmput() and after that
> > this memory can be freed and re-used as another mm_struct.
> >
>
> Before we do a mmput(), we take the mmap_sem for that mm. So this mm
> cannot be freed until we complete insertion/removal. If the mm gets
> reused after the insertion/removal, and maps the inode,
Yes, see the previous email from me, we can rely on uprobe_mmap().
> Or are you hinting at some other problem?
Perhaps this deserves a comment. I mean, to explain that yes,
tmpvi->mm == vma->vm_mm can be wrong but this is fine.
However, I hope we simply can kill this code. See build_map_info()
I sent.
Oleg.
next prev parent reply other threads:[~2012-06-01 18:40 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 [this message]
2012-05-31 12:15 ` Peter Zijlstra
2012-05-31 12:54 ` Srikar Dronamraju
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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