Re: inconsistent lock state in ima_process_queued_keys

[Lakshmi Ramasubramanian]

I am investigating this.

thanks,
 -lakshmi

On 1/14/2020 7:21 AM, Dmitry Vyukov wrote:
> On Tue, Jan 14, 2020 at 3:57 PM Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote:
> > On Tue, 2020-01-14 at 14:58 +0100, Dmitry Vyukov wrote:
> > > On Tue, Jan 14, 2020 at 2:56 PM syzbot
> > > <syzbot+a4a503d7f37292ae1664@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> > > > Hello,
> > > >
> > > > syzbot found the following crash on:
> > > >
> > > > HEAD commit:    1b851f98 Add linux-next specific files for 20200114
> > > > git tree:       linux-next
> > > > console output: https://syzkaller.appspot.com/x/log.txt?x=12bcbb25e00000
> > > > kernel config:  https://syzkaller.appspot.com/x/.config?x=3e7d9cf7ebfa08ad
> > > > dashboard link: https://syzkaller.appspot.com/bug?extid=a4a503d7f37292ae1664
> > > > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > > >
> > > > Unfortunately, I don't have any reproducer for this crash yet.
> > > >
> > > > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > > > Reported-by: syzbot+a4a503d7f37292ae1664@xxxxxxxxxxxxxxxxxxxxxxxxx
> > >
> > > +Lakshmi, you seem to have submitted a number of changes to this file recently.
> > >
> > > This completely breaks linux-next testing for us, every kernel crashes
> > > a few minutes after boot.
> > >
> > > 2020/01/14 14:45:00 vm-26: crash: inconsistent lock state in
> > > ima_process_queued_keys
> >
> > Yikes!  Are you running with an IMA policy?
>
> I don't know.
>
> >   I assume this is being
> > caused by commit 8f5d2d06f217 ("IMA: Defined timer to free queued
> > keys".  Does reverting it prevent this from happening?
>
> The following seems to help, but don't know if it's the right fix or not.
>
> diff --git a/security/integrity/ima/ima_asymmetric_keys.c
> b/security/integrity/ima/ima_asymmetric_keys.c
> index 61e478f9e8199..49d559501fe62 100644
> --- a/security/integrity/ima/ima_asymmetric_keys.c
> +++ b/security/integrity/ima/ima_asymmetric_keys.c
> @@ -103,17 +103,18 @@ static bool ima_queue_key(struct key *keyring,
> const void *payload,
>   {
>          bool queued = false;
>          struct ima_key_entry *entry;
> +       unsigned long flags;
>
>          entry = ima_alloc_key_entry(keyring, payload, payload_len);
>          if (!entry)
>                  return false;
>
> -       spin_lock(&ima_keys_lock);
> +       spin_lock_irqsave(&ima_keys_lock, flags);
>          if (!ima_process_keys) {
>                  list_add_tail(&entry->list, &ima_keys);
>                  queued = true;
>          }
> -       spin_unlock(&ima_keys_lock);
> +       spin_unlock_irqrestore(&ima_keys_lock, flags);
>
>          if (!queued)
>                  ima_free_key_entry(entry);