clockevents: Warn if cpu_all_mask is used as cpumask
commitfbfa9260085b5b578a049a90135e5c51928c5f7f
authorSudeep Holla <sudeep.holla@arm.com>
Wed, 11 Jul 2018 11:24:24 +0000 (11 12:24 +0100)
committerThomas Gleixner <tglx@linutronix.de>
Thu, 2 Aug 2018 12:55:53 +0000 (2 14:55 +0200)
tree43eadbc7349ce78a8b5b173abb068a1e2d6d5ae1
parent234b3840d73430564a03f53973a311b7a83a95a9
clockevents: Warn if cpu_all_mask is used as cpumask

Using cpu_all_mask in clockevents cpumask may result in issues while
comparing multiple clockevent devices to choose the preferred one.

On one of the platforms with 2 system (i.e. non per-CPU) timers with
different ratings, having cpu_all_mask for one of the device resulted in a
boot hang due to a endless loop in clockevents_notify_released() as both
were clocksources were selected as preferred.

In order to prevent such issues in the future, warn if any clockevent
driver sets cpu_all_mask as it's cpumask and just override it to use
cpu_possible_mask. All the existing occurrences of cpu_all_mask are already
replaced with cpu_possible_mask.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lkml.kernel.org/r/1531308264-24220-3-git-send-email-sudeep.holla@arm.com
kernel/time/clockevents.c