Re: [stable] [PATCH] - fix oops in sysfs_readdir

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 21 May 2007 19:18:55 -0500 Eric Sandeen <sandeen@redhat.com> wrote:

> Andrew Morton wrote:
> > On Mon, 21 May 2007 13:11:21 -0500
> > Eric Sandeen <sandeen@redhat.com> wrote:
> > 
> >> This is a non-ida backport of Tejun's patch in -mm at:
> >> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.22-rc1/2.6.22-rc1-mm1/broken-out/gregkh-driver-sysfs-allocate-inode-number-using-ida.patch
> >> for the 2.6.16 -stable tree - it follows the same scheme of using s_ino to safely
> >> store & retrieve the inode number of sysfs entries for use in sysfs_readdir,
> >> but uses a brain-dead-simple inode nr allocator rather than ida, which would
> >> bring along a lot of newer, more complex code.
> >>
> >> No, this doesn't guarantee uniqueness of sysfs inode numbers, but then
> >> the code in -stable today doesn't either - and with this change, at least
> >> it shouldn't oops.
> > 
> > So I'm sitting here whether to commend this patch to google kernel maintainers
> > for 2.6.18 backport, but I realise I don't know what it does.  And I don't know
> > if it fixes the reclaim-time oopses they were intermittently seeing, or if it
> > fixes something else and if so what that is.
> > 
> > Sigh.  Better changelogs, please.
> > 
> 
> Sorry Andrew.  I referenced Tejun's upstream patch in -mm which has a 
> nice changelog etc, and this is a backport of that, and does the same 
> thing in the same way and solves the same problem - but that doesn't 
> help if you just want to toss this message into your patch stack.  Will 
> fix up & resend.
> 

Actually, someone (eg distros) looking at Tejun's changelog would still be
struggling to answer the question "do I need this".  The one thing it
claims to fix is "duplicate inode numbers".  But why is that a problem? 
What are the user-visible consequences of not merging the patch?  Unobvious.