sched/isolation: Fix housekeeping_mask memory leak

If "nohz_full=" or "isolcpus=nohz" are called with CONFIG_NO_HZ_FULL=n,
housekeeping_mask doesn't get freed despite it being unused if
housekeeping_setup() is called for the first time.

Check this scenario first to fix this, so that no useless allocation
is performed.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Link: https://lore.kernel.org/r/20220207155910.527133-8-frederic@kernel.org

diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 828dacec483e55eb6740c3cf8fd6b159246dec91..883eee9fae229bea259d5d7e558ef7e9800993fe 100644 (file)
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -94,6 +94,14 @@ static int __init housekeeping_setup(char *str, enum hk_flags flags)
        cpumask_var_t non_housekeeping_mask, housekeeping_staging;
        int err = 0;
 
+       if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) {
+               if (!IS_ENABLED(CONFIG_NO_HZ_FULL)) {
+                       pr_warn("Housekeeping: nohz unsupported."
+                               " Build with CONFIG_NO_HZ_FULL\n");
+                       return 0;
+               }
+       }
+
        alloc_bootmem_cpumask_var(&non_housekeeping_mask);
        if (cpulist_parse(str, non_housekeeping_mask) < 0) {
                pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n");
@@ -123,15 +131,8 @@ static int __init housekeeping_setup(char *str, enum hk_flags flags)
                }
        }
 
-       if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) {
-               if (IS_ENABLED(CONFIG_NO_HZ_FULL)) {
-                       tick_nohz_full_setup(non_housekeeping_mask);
-               } else {
-                       pr_warn("Housekeeping: nohz unsupported."
-                               " Build with CONFIG_NO_HZ_FULL\n");
-                       goto free_housekeeping_staging;
-               }
-       }
+       if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK))
+               tick_nohz_full_setup(non_housekeeping_mask);
 
        housekeeping_flags |= flags;
        err = 1;