Comment # 1 on bug 1047651 from Takashi Iwai

Gah, that's bad.  It's a kernel BUG() that was introduced by 4.4.21 stable, the
backport of commit 9006a01829a50cfd6bbd4980910ed46e895e93d7
    hrtimer: Catch illegal clockids

But the commit was later reverted by the commit
82e88ff1ea948d83125a8aaa7c9809f03ccc500f

    hrtimer: Revert CLOCK_MONOTONIC_RAW support

    Revert commits:
    a6e707ddbdf1: KVM: arm/arm64: timer: Switch to CLOCK_MONOTONIC_RAW
    9006a01829a5: hrtimer: Catch illegal clockids
    9c808765e88e: hrtimer: Add support for CLOCK_MONOTONIC_RAW

    Marc found out, that there are fundamental issues with that patch series
    because __hrtimer_get_next_event() and hrtimer_forward() need support for
    CLOCK_MONOTONIC_RAW. Nothing which is easily fixed, so revert the whole
lot.

But this fix doesn't seem taken by the upstream.
Interestingly, the check was revived by the later commit
336a9cde10d641e70bac67d90ae91b3190c3edca
    hrtimer: Catch invalid clockids again

but now with a WARN() instead of BUG().  So we'll see the kernel Oops but not a
panic, at least.

The real culprit is, however, the call site in mac80211_hwsim.c.
This was fixed by the commit 8fbcfeb8a9cc803464d6c166e7991913711c612c
    mac80211_hwsim: Replace bogus hrtimer clockid

This has to be backported.