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Subject: Re: [PATCH v3 2.6.39-rc1-tip 9/26]  9: uprobes: mmap and fork hooks.
From: Peter Zijlstra <peterz@infradead.org>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>, Linux-mm <linux-mm@kvack.org>, Arnaldo Carvalho de Melo <acme@infradead.org>, Linus Torvalds <torvalds@linux-foundation.org>, Jonathan Corbet <corbet@lwn.net>, Christoph Hellwig <hch@infradead.org>, Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,  Thomas Gleixner <tglx@linutronix.de>, Ananth N Mavinakayanahalli <ananth@in.ibm.com>, Oleg Nesterov <oleg@redhat.com>, LKML <linux-kernel@vger.kernel.org>, SystemTap <systemtap@sources.redhat.com>, Jim Keniston <jkenisto@linux.vnet.ibm.com>, Roland McGrath <roland@hack.frob.com>, Andi Kleen <andi@firstfloor.org>, Andrew Morton <akpm@linux-foundation.org>
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Date: Mon, 18 Apr 2011 16:22:00 -0000
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On Fri, 2011-04-01 at 20:04 +0530, Srikar Dronamraju wrote:
> +       if (vma) {
> +               /*
> +                * We get here from uprobe_mmap() -- the case where we
> +                * are trying to copy an instruction from a page that's
> +                * not yet in page cache.
> +                *
> +                * Read page in before copy.
> +                */
> +               struct file *filp =3D vma->vm_file;
> +
> +               if (!filp)
> +                       return -EINVAL;
> +               page_cache_sync_readahead(mapping, &filp->f_ra, filp, idx=
, 1);
> +       }
> +       page =3D grab_cache_page(mapping, idx);=20

So I don't see why that isn't so for the normal install_uprobe() <-
register_uprobe() path.