From: John Hubbard <jhubbard@xxxxxxxxxx>
Commit 8fcf2cc768acd845c1fed837bf9cfe2d7106336d in linux-next
introduced a regression in some configurations. Specifically,
with CONFIG_NO_HZ_FULL set, and CONFIG_NO_HZ_FULL_ALL *not* set,
the kernel will crash in lockup_detector_init(), due to a
NULL tick_nohz_full_init pointer.
This is because the above commit uses tick_nohz_full_init
(in lockup_detector_init), if CONFIG_NO_HZ_FULL is set, but
tick_nohz_full_init only gets allocated if either:
a) CONFIG_NO_HZ_FULL_ALL is set, or
b) Someone passes in nohz_full=<any_value> on the boot
args line.
To correct this, change the allocation site (case a, above):
allocate tick_nohz_full_init whenever CONFIG_NO_HZ_FULL is set.
Also, change the enclosing function name to more accurately
reflect its current role.
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
---
kernel/time/tick-sched.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 9142591..b21ee28 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -326,11 +326,11 @@ static int tick_nohz_cpu_down_callback(struct notifier_block *nfb,
return NOTIFY_OK;
}
-static int tick_nohz_init_all(void)
+static int tick_nohz_full_init(void)
{
int err = -1;
-#ifdef CONFIG_NO_HZ_FULL_ALL
+#ifdef CONFIG_NO_HZ_FULL
if (!alloc_cpumask_var(&tick_nohz_full_mask, GFP_KERNEL)) {
WARN(1, "NO_HZ: Can't allocate full dynticks cpumask\n");
return err;
@@ -347,7 +347,7 @@ void __init tick_nohz_init(void)
int cpu;
if (!tick_nohz_full_running) {
- if (tick_nohz_init_all() < 0)
+ if (tick_nohz_full_init() < 0)
return;
}
--
2.3.7
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