linux-kernel - [PATCH 1/1] platform/x86/intel/ifs: release cpus_read

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Date:   Wed, 27 Sep 2023 11:48:24 -0700
From:   Jithu Joseph <jithu.joseph@...el.com>
To:     hdegoede@...hat.com, markgross@...nel.org
Cc:     ashok.raj@...el.com, tony.luck@...el.com,
        linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        patches@...ts.linux.dev
Subject: [PATCH 1/1] platform/x86/intel/ifs: release cpus_read_lock()

Couple of error paths in do_core_test() was returning directly without
doing a necessary cpus_read_unlock().

Following lockdep warning was observed when exercising these scenarios
with PROVE_RAW_LOCK_NESTING enabled:

[  139.304775] ================================================
[  139.311185] WARNING: lock held when returning to user space!
[  139.317593] 6.6.0-rc2ifs01+ #11 Tainted: G S      W I
[  139.324499] ------------------------------------------------
[  139.330908] bash/11476 is leaving the kernel with locks still held!
[  139.338000] 1 lock held by bash/11476:
[  139.342262]  #0: ffffffffaa26c930 (cpu_hotplug_lock){++++}-{0:0}, at:
do_core_test+0x35/0x1c0 [intel_ifs]

Fix the flow so that all scenarios release the lock prior to returning
from the function.

Fixes: 5210fb4e1880 ("platform/x86/intel/ifs: Sysfs interface for Array BIST")
Cc: stable@...r.kernel.org
Signed-off-by: Jithu Joseph <jithu.joseph@...el.com>
---
 drivers/platform/x86/intel/ifs/runtest.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/intel/ifs/runtest.c b/drivers/platform/x86/intel/ifs/runtest.c
index 1061eb7ec399..43c864add778 100644
--- a/drivers/platform/x86/intel/ifs/runtest.c
+++ b/drivers/platform/x86/intel/ifs/runtest.c
@@ -331,14 +331,15 @@ int do_core_test(int cpu, struct device *dev)
 	switch (test->test_num) {
 	case IFS_TYPE_SAF:
 		if (!ifsd->loaded)
-			return -EPERM;
-		ifs_test_core(cpu, dev);
+			ret = -EPERM;
+		else
+			ifs_test_core(cpu, dev);
 		break;
 	case IFS_TYPE_ARRAY_BIST:
 		ifs_array_test_core(cpu, dev);
 		break;
 	default:
-		return -EINVAL;
+		ret = -EINVAL;
 	}
 out:
 	cpus_read_unlock();

base-commit: 6465e260f48790807eef06b583b38ca9789b6072
-- 
2.25.1