Messages in this thread | | | Date | Tue, 17 Mar 2009 20:53:47 +0800 | From | Zhang Le <> | Subject | Re: [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
| |