Re: Linux 4.2-rc1

[Casey Schaufler <casey@schaufler-ca.com>]

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On 7/8/2015 11:07 AM, William Roberts wrote:
>
>
> On Wed, Jul 8, 2015 at 10:47 AM, Casey Schaufler
> <casey@schaufler-ca.com <mailto:casey@schaufler-ca.com>> wrote:
>
>     On 7/8/2015 10:29 AM, Linus Torvalds wrote:
>     > On Wed, Jul 8, 2015 at 10:17 AM, Linus Torvalds
>     > <torvalds@linux-foundation.org
>     <mailto:torvalds@linux-foundation.org>> wrote:
>     >> Decoding the "Code:" line shows that this is the "->fw_id"
>     dereference in
>     >>
>     >>         if (add_uevent_var(env, "FIRMWARE=%s",
>     fw_priv->buf->fw_id))
>     >>                 return -ENOMEM;
>     >>
>     >> and that "fw_priv->buf" pointer is NULL.
>     >>
>     >> However, I don't see anything that looks like it should have
>     changed
>     >> any of this since 4.1.
>     > Looking at the otehr uses of "fw_priv->buf", they all check that
>     > pointer for NULL. I see code like
>     >
>     >         fw_buf = fw_priv->buf;
>     >         if (!fw_buf)
>     >                 goto out;
>     >
>     > etc.
>     >
>     > Also, it looks like you need to hold the "fw_lock" to even look at
>     > that pointer, since the buffer can get reallocated etc.
>     >
>     > So that uevent code really looks buggy. It just doesn't look like a
>     > *new* bug to me. That code looks old, going back to 2012 and commit
>     > 1244691c73b2.
>
>     There have been SELinux changes to kernfs for 4.2. William,
>     you might want to have a look here.
>
>
> My changes were never merged AFAIK and can tell. I was still working
> on this
> but we had some changes internally to SELinux that let us handle this,
> although
> we should correct this on kernfs at some point, its low priority for
> me now. Also
> commit fb029 makes kernfs_get_inode() public, so I need to rethink
> some things.

OK, false alarm. Not an SELinux issue. It might be useful
to see if the problem occurs with AppArmor off.

>  
>
>
>     >
>     > Ming Lei?
>     >
>     >                  Linus
>     > --
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> -- 
> Respectfully,
>
> William C Roberts
>


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