"kernel NULL pointer dereference" crash when attempting a write

[Casey Schaufler]

On 1/25/2022 11:57 AM, Paul Moore wrote:
> On Tue, Jan 25, 2022 at 12:09 PM Casey Schaufler <casey at schaufler-ca.com> wrote:
>> On 1/25/2022 7:56 AM, Vivek Goyal wrote:
>>> On Tue, Jan 25, 2022 at 07:32:19AM -0500, Jeff Layton wrote:
>>>> On Tue, 2022-01-25 at 13:12 +0100, Christian Brauner wrote:
>>>>> On Tue, Jan 25, 2022 at 06:25:39AM -0500, Jeff Layton wrote:
>>>>>> On Tue, 2022-01-25 at 12:13 +0100, Christian Brauner wrote:
>>>>>>> On Tue, Jan 25, 2022 at 05:54:57AM -0500, Jeff Layton wrote:
>>>>>>>> On Mon, 2022-01-24 at 21:45 -0500, Paul Moore wrote:
>>>>>>>>> On Mon, Jan 24, 2022 at 8:51 PM Stephen Muth <smuth4 at gmail.com> wrote:
> ...
>
>> Joining the conversation late. Wish someone had brought me
>> in sooner.
> For some reason I thought the LSM list was on the To/CC line, my
> mistake (fixed now).
>
> Thanks to everyone for all of the further discussion, review on this;
> I plucked the original post out of my spam folder as I was shutting
> down for the night yesterday and only gave it a quick look.
>
>>> Looks like dentry_init_security() can't handle multiple LSMs. We probably
>>> should disallow all other LSMs to register a hook for this and only
>>> allow SELinux to register a hook.
>> Not acceptable. The fix to dentry_init_security() is easy.
> Sounds good to me, Vivek did you want to put together a patch for
> this?  If not, let me know and I'll put one together.

Thank you. I'd do it myself, but I'm dealing with pain meds and a
hinky keyboard. Rarely a great start for a good patch.