Re: [PATCH v2 5/5] exec: Add a exec_update_mutex to replace cred_guard_mutex

[Bernd Edlinger]

On 3/12/20 3:38 PM, Eric W. Biederman wrote:
> Kirill Tkhai <ktkhai@xxxxxxxxxxxxx> writes:
> 
>> On 12.03.2020 15:24, Eric W. Biederman wrote:
>>>
>>> I actually need to switch the lock ordering here, and I haven't yet
>>> because my son was sick yesterday.

All the best wishes to you and your son.  I hope he will get well soon.

And sorry for not missing the issue in the review.  The reason turns
out that bprm_mm_init is called after prepare_bprm_creds, but there
are error pathes between those where free_bprm is called up with
cred != NULL and mm == NULL, but the mutex not locked.

I figured out a possible fix for the problem that was pointed out: