[tip:timers/core] hrtimer: Handle failure of tick_init_highres() gracefully

[tip-bot for Guenter Roeck <tipbot@zytor.com>]

Commit-ID:  85e1cd6e769dfc84995270d0a4838021fcb8602d
Gitweb:     http://git.kernel.org/tip/85e1cd6e769dfc84995270d0a4838021fcb8602d
Author:     Guenter Roeck <linux@roeck-us.net>
AuthorDate: Sat, 22 Aug 2015 01:10:47 -0700
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sat, 22 Aug 2015 10:57:50 +0200

hrtimer: Handle failure of tick_init_highres() gracefully

Commit 75e3b37d0598 ("hrtimer: Drop return code of hrtimer_switch_to_hres()")
drops the return code of hrtimer_switch_to_hres(). While doing so, it also
drops the return statement itself on failure. This may cause a system hang.
Seen when running arm:multi_v7_defconfig in qemu with devicetree file
vexpress-v2p-ca9.

Fixes: 75e3b37d0598 ("hrtimer: Drop return code of hrtimer_switch_to_hres()")
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: http://lkml.kernel.org/r/1440231047-16256-1-git-send-email-linux@roeck-us.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/time/hrtimer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 5c4fe50..457a373 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -695,6 +695,7 @@ static void hrtimer_switch_to_hres(void)
 	if (tick_init_highres()) {
 		printk(KERN_WARNING "Could not switch to high resolution "
 				    "mode on CPU %d\n", base->cpu);
+		return;
 	}
 	base->hres_active = 1;
 	hrtimer_resolution = HIGH_RES_NSEC;