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    SubjectRe: [PATCH] filp->f_pos not correctly updated in proc_task_readdir
    On 08:34 Mon 16 Mar     , Al Viro wrote:
    > On Mon, Mar 16, 2009 at 02:44:31PM +0800, Zhang Le wrote:
    > > filp->f_pos only get updated at the end of the function. Thus d_off of those
    > > dirents who are in the middle will be 0, and this will cause a problem in
    > > glibc's readdir implementation, specifically endless loop. Because when overflow
    > > occurs, f_pos will be set to next dirent to read, however it will be 0, unless
    > > the next one is the last one. So it will start over again and again.
    > Eh... Here's what's really going on:
    > proc_..._fill_cache() API is rather kludgy and far too convoluted. In
    > particular, it calls filldir() and passes file->f_pos to it, expecting
    > the caller to update file->f_pos between the calls. proc_task_readdir()
    > uses that sucker, but doesn't update ->f_pos until the very end. As
    > the result, d_off of direntries produced by it gets screwed.
    > Broken-by: commit 61a28784028e6d55755e4d0f39bee8d9bf2ee8d9
    > Author: Eric W. Biederman <>
    > Date: Mon Oct 2 02:18:49 2006 -0700
    > [PATCH] proc: Remove the hard coded inode numbers

    Thanks for sharing the insights.

    > Patch is fine, but I'd rather rip the layers of ..._fill_cache() abstractions
    > out and see what falls out. Anyway, for -rc your variant is definitely the
    > way to go.

    So, will you take care of it? Or who else should I ask? Thanks in advance!

    Zhang, Le

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