[PATCH] sched/ext: fix cpumask leak in scx_init() error path

[KobaK <kobak@nvidia.com>]

From: Koba Ko <kobak@nvidia.com>

In scx_init(), two cpumask allocations are combined with || short-circuit
evaluation. If the first alloc_cpumask_var (scx_bypass_lb_donee_cpumask)
succeeds but the second (scx_bypass_lb_resched_cpumask) fails, the first
cpumask is leaked.

Split the allocations into separate checks with per-allocation error
messages and free the first cpumask when the second allocation fails.

Fixes: 95d1df610cdc7 ("sched_ext: Implement load balancer for bypass mode")
Signed-off-by: Koba Ko <kobak@nvidia.com>
---
 kernel/sched/ext.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index b757b853b42bb..0648088a76f09 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -9662,9 +9662,14 @@ static int __init scx_init(void)
 		return ret;
 	}
 
-	if (!alloc_cpumask_var(&scx_bypass_lb_donee_cpumask, GFP_KERNEL) ||
-	    !alloc_cpumask_var(&scx_bypass_lb_resched_cpumask, GFP_KERNEL)) {
-		pr_err("sched_ext: Failed to allocate cpumasks\n");
+	if (!alloc_cpumask_var(&scx_bypass_lb_donee_cpumask, GFP_KERNEL)) {
+		pr_err("sched_ext: Failed to allocate donee cpumask\n");
+		return -ENOMEM;
+	}
+
+	if (!alloc_cpumask_var(&scx_bypass_lb_resched_cpumask, GFP_KERNEL)) {
+		pr_err("sched_ext: Failed to allocate resched cpumask\n");
+		free_cpumask_var(scx_bypass_lb_donee_cpumask);
 		return -ENOMEM;
 	}
 
-- 
2.43.0