Re: [PATCH] audit: grab a reference to context->pwd when it's cached
On Thu, 4 Oct 2012 11:48:23 -0700
Peter Moody <pmoody(a)google.com> wrote:
On Wed, Sep 26, 2012 at 6:50 AM, Alexander Viro
<aviro(a)redhat.com> wrote:
> On Tue, Sep 25, 2012 at 10:03:23AM -0700, Peter Moody wrote:
>> Hey folks,
>>
>> following up on old patches, are there any comments on this? Did you
>> get around to finding a better way to fix this bug, Al?
>
> Alas, I've found none ;-/ Looks like we'll have to go with this one,
> at least until somebody comes up with better solution.
Not surprisingly, this patch doesn't actually fix the issue (or at
least doesn't do it correctly).
I hadn't noticed that get_fs_pwd() actually calls path_get() on
&context->pwd so the additional path_get() is useless and the
reference doesn't ever actually get freed if audit_putname is called
while we're in a syscall.
Al, Eric, Jeff; do any of you guys have an understanding of what the
initial bug actually is since this clearly doesn't fix it?
Cheers,
peter
BTW, I ran this test on one of my KVM guests and it ran just fine. That
one is an x86_64 guest running a 3.6.0+ kernel. The root fs on there is
ext4 though, not ext3. So perhaps that's a factor?
The oops message you posted at least looks like something down in the
bowels of ext3 or fs/buffer.c.
--
Jeff Layton <jlayton(a)redhat.com>