[PATCH AUTOSEL 5.4 026/107] x86/resctrl: Fix potential memory leak

[Sasha Levin]

From: Shakeel Butt <shakeelb@xxxxxxxxxx>

[ Upstream commit ab6a2114433a3b5b555983dcb9b752a85255f04b ]

set_cache_qos_cfg() is leaking memory when the given level is not
RDT_RESOURCE_L3 or RDT_RESOURCE_L2. At the moment, this function is
called with only valid levels but move the allocation after the valid
level checks in order to make it more robust and future proof.

 [ bp: Massage commit message. ]

Fixes: 99adde9b370de ("x86/intel_rdt: Enable L2 CDP in MSR IA32_L2_QOS_CFG")
Signed-off-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: x86-ml <x86@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200102165844.133133-1-shakeelb@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 2e3b06d6bbc6d..dac7209a07084 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1741,9 +1741,6 @@ static int set_cache_qos_cfg(int level, bool enable)
 	struct rdt_domain *d;
 	int cpu;
 
-	if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
-		return -ENOMEM;
-
 	if (level == RDT_RESOURCE_L3)
 		update = l3_qos_cfg_update;
 	else if (level == RDT_RESOURCE_L2)
@@ -1751,6 +1748,9 @@ static int set_cache_qos_cfg(int level, bool enable)
 	else
 		return -EINVAL;
 
+	if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
+		return -ENOMEM;
+
 	r_l = &rdt_resources_all[level];
 	list_for_each_entry(d, &r_l->domains, list) {
 		/* Pick one CPU from each domain instance to update MSR */
-- 
2.20.1