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    SubjectRe: [PATCH] filp->f_pos not correctly updated in proc_task_readdir
    On 13:37 Tue 17 Mar     , Alexey Dobriyan wrote:
    > On Mon, Mar 16, 2009 at 08:34:57AM +0000, 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 <ebiederm@xmission.com>
    > > Date: Mon Oct 2 02:18:49 2006 -0700
    > >
    > > [PATCH] proc: Remove the hard coded inode numbers
    > >
    > > 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.
    >
    > Except this bit:
    >
    > fs/built-in.o: In function `proc_task_readdir':
    > compr_zlib.c:(.text+0x434b8): undefined reference to `__cmpdi2'
    > compr_zlib.c:(.text+0x434d4): undefined reference to `__cmpdi2'

    Hi, I am sorry but I can't reproduce this.
    Are you sure this only happens after applying my patch?
    Would you please provide your fs/jffs2/compr_zlib.o and fs/proc/base.o?
    And what is your gcc version? I am using gcc 4.4 snapshot rev. 144705
    Thanks!

    Zhang, Le
    http://zhangle.is-a-geek.org


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