Re: [IMA] 11b771ffff: BUG:sleeping_function_called_from_invalid_context_at_kernel/locking/mutex.c

[Mimi Zohar]

Hi Lakshmi,

On Fri, 2019-12-27 at 22:23 +0800, kernel test robot wrote:
> [  333.455345] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:281
> [  333.457243] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 12395, name: userfaultfd
> [  333.458888] CPU: 1 PID: 12395 Comm: userfaultfd Not tainted 5.5.0-rc1-00011-g11b771ffff8fc #1
> [  333.461096] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> [  333.463893] Call Trace:
> [  333.465287]  <IRQ>
> [  333.466351]  dump_stack+0x66/0x8b
> [  333.467346]  ___might_sleep+0x102/0x120
> [  333.468385]  mutex_lock+0x1c/0x40
> [  333.469421]  ima_process_queued_keys+0x24/0x110
> [  333.470529]  ? ima_process_queued_keys+0x110/0x110
> [  333.471656]  call_timer_fn+0x2d/0x140
> [  333.472707]  run_timer_softirq+0x46f/0x4b0
> [  333.473752]  ? enqueue_hrtimer+0x39/0xa0
> [  333.474780]  __do_softirq+0xe3/0x2f8
> [  333.475768]  irq_exit+0xd5/0xe0
> [  333.476738]  smp_apic_timer_interrupt+0x74/0x140
> [  333.477834]  apic_timer_interrupt+0xf/0x20
> [  333.478858]  </IRQ>

I think this is an instance where defining timer_expired as atomic and
then testing it using atomic_dec_and_test() would help. ÂEither the
queued keys would be deleted in ima_timer_handler() or measured in
ima_process_queued_keys().

Mimi