In kernel/sched/core.c, there is:
static int init_rootdomain(struct root_domain *rd)
{
memset(rd, 0, sizeof(*rd));
if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
goto out;
if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
goto free_span;
if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
goto free_online;
if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
goto free_dlo_mask;
In the CONFIG_CPUMASK_OFFSTACK=y case, there doesn't appear to be anything
clearing the cpumasks. I think these should be zalloc_cpumask_var() calls.
I noticed this while debugging a memory corruptor in unrelated code which
cleared the span cpumask and triggered a BUG in the scheduler. I had turned
on CONFIG_PAGE_POISONING and looking at the span cpumask at various points
during early boot and saw that the mask was filled with POISON_FREE bytes
before the secondary cores started coming up and setting their cpu bits in
the mask.
Signed-off-by: Mark Salter <msal...@redhat.com>
---
kernel/sched/core.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f5c6635..9843755 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5355,13 +5355,13 @@ static int init_rootdomain(struct root_domain *rd)
{
memset(rd, 0, sizeof(*rd));
- if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
+ if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
goto out;
- if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
+ if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
goto free_span;
- if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
+ if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
goto free_online;
- if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
+ if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
goto free_dlo_mask;
init_dl_bw(&rd->dl_bw);
--
1.8.5.3
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