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From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <peterz@infradead.org>,
	Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
	Anton Arapov <anton@redhat.com>, Hugh Dickins <hughd@google.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 4/5] uprobes: cleanup and document write_opcode()->lock_page(old_page)
Date: Mon, 9 Jul 2012 15:59:22 +0530	[thread overview]
Message-ID: <20120709102922.GD32393@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120624150053.GD23277@redhat.com>

* Oleg Nesterov <oleg@redhat.com> [2012-06-24 17:00:53]:

> The comment above write_opcode()->lock_page(old_page) tells about
> the race with do_wp_page(). I don't really understand which exactly
> race it means, but afaics this lock_page() was not enough to close
> all races with do_wp_page().
> 
> Anyway, since 77fc4af1 this code is always called with ->mmap_sem
> hold for writing so we can forget about do_wp_page().
> 
> However, we can't simply remove this lock_page(), and the only
> (afaics) reason is __replace_page()->try_to_free_swap().
> 
> Nothing in write_opcode() needs it, move it into __replace_page()
> and fix the comment.
> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>


  reply	other threads:[~2012-07-09 10:29 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-24 14:59 [PATCH v2 0/5] uprobes: write_opcode() cleanups Oleg Nesterov
2012-06-24 15:00 ` [PATCH v2 1/5] uprobes: don't recheck vma/f_mapping in write_opcode() Oleg Nesterov
2012-07-09 10:30   ` Srikar Dronamraju
2012-06-24 15:00 ` [PATCH v2 2/5] uprobes: __replace_page() should not use page_address_in_vma() Oleg Nesterov
2012-07-06 16:18   ` Oleg Nesterov
2012-07-09 10:28     ` Srikar Dronamraju
2012-06-24 15:00 ` [PATCH v2 3/5] uprobes: kill write_opcode()->lock_page(new_page) Oleg Nesterov
2012-07-09 10:29   ` Srikar Dronamraju
2012-06-24 15:00 ` [PATCH v2 4/5] uprobes: cleanup and document write_opcode()->lock_page(old_page) Oleg Nesterov
2012-07-09 10:29   ` Srikar Dronamraju [this message]
2012-06-24 15:01 ` [PATCH v2 5/5] uprobes: __replace_page() needs munlock_vma_page() Oleg Nesterov
2012-06-26 11:55   ` Anton Arapov
2012-06-26 15:47     ` Oleg Nesterov
2012-07-06 10:54 ` [PATCH v2 0/5] uprobes: write_opcode() cleanups Ingo Molnar
2012-07-06 16:07   ` Oleg Nesterov
2012-07-06 16:13     ` Oleg Nesterov
2012-07-09  9:12       ` Ingo Molnar
2012-07-09 13:30         ` Oleg Nesterov
2012-07-09 10:27     ` Srikar Dronamraju

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