Messages in this thread | | | Date | Tue, 17 Mar 2009 00:27:20 +0800 | From | Zhang Le <> | Subject | Re: [PATCH] filp->f_pos not correctly updated in proc_task_readdir |
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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 <ebiederm@xmission.com> > 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 http://zhangle.is-a-geek.org
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