Re: [PATCH] sanity.bbclass: Reading /proc/sys/vm/mmap_min_addr is not permitted with 2.6.33+ on host

[Martin Jansa <martin.jansa@gmail.com>]

On Sat, Jan 02, 2010 at 06:10:05PM +0000, Phil Blundell wrote:
> On Sat, 2010-01-02 at 18:10 +0100, Martin Jansa wrote:
> > * With 2.6.33-rc2-00252-ge9e5521 on my host I noticed that
> >   "cat /proc/sys/vm/mmap_min_addr" returns now
> >   "cat: /proc/sys/vm/mmap_min_addr: Operation not permitted"
> >   Its probably becuse of
> >   http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=0e1a6ef2dea88101b056b6d9984f3325c5efced3
> >   But I'm not sure if checking CAP_SYS_RAWIO even for reading this value
> >   is intentional or just bug which should be fixed in kernel.
> > 
> > * This patch prints notice about need to check that value yourself (as
> >   root) instead of failing with "ERROR: IO Error: [Errno 1] Operation
> >   not permitted"
> > 
> > * Its not optimal, because this notice is shown every time you run
> >   bitbake (even after checking/setting 0 to mmap_min_addr if you have
> >   kernel not allowing to read it
> > 
> 
> That does sound fairly unsatisfactory.  Printing a diagnostic on every
> build, with no way for the user to suppress it, surely can't be the way
> of the future.

Yes, agreed. I consider this only as temporary solution, because 
without this change I cannot use bitbake at all and of course I can
remove that message if this behavior stay the same in 2.6.33 release or
someone check qemu mmap failure.

That's why I didn't push it and just sent it here as heads up for
builders with 2.6.33-rc* to save tham few mins checking what happen to
bitbake.

> If you can't tell whether mmap_min_addr is set correctly or not then it
> would probably be better to not show the diagnostic at all.  Perhaps you
> could investigate patching qemu to print a more meaningful message if it
> actually encounters a mmap() failure of this kind.

Cheers,

-- 
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Jansa Martin                 sip:jamasip@voip.wengo.fr 
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