Re: [2.6 patch] unexport uts_sem
From: Christoph Hellwig
Date: Wed May 21 2008 - 08:37:22 EST
On Tue, May 20, 2008 at 02:38:02PM -0400, Frank Ch. Eigler wrote:
> Sorry, I misspoke - this check is intended not to cross-check
> kernel-devel and the kernel itself, but the debuginfo or similar data
> that is given to describe target of a systemtap script. I guess for
> new enough kernels we'll just do that using buildid hash codes.
> By the way, there do appear to be a few suspect in-tree users of
> utsname() without uts_sem locking (usb/storage/usb.c
Just a debug printk. Note sure why this particular one needs to
print the version, but if it really wants to do it it should rather use
This one is quite fishy. Not sure what it needs the name for but the
kernel utsname is probably a bad choise. And yes, this one actually
is racy because the host name can change.
random.c is always built-in and utsname is called during the
single-threaded kernel initialization phase, so this is safe.
> fs/lockd/clntproc.c, ...).
Yes, this one is racy. Should probably be fixed by starting lockd
with CLONE_NEWUTS so that it never changed during it's lifetime.
It's probably not a good idea when it changes with outstanding lockd
> If these need to be fixed,
> then wouldn't uts_sem need to come back exported?
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