linux-kernel - [PATCH v4 3/5] kernel/cpu_pm: Fix uninitted local in cpu

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Message-Id: <20200422145408.v4.3.I2d44fc0053d019f239527a4e5829416714b7e299@changeid>
Date:   Wed, 22 Apr 2020 14:55:01 -0700
From:   Douglas Anderson <dianders@...omium.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        rafael.j.wysocki@...el.com, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     mka@...omium.org, swboyd@...omium.org, mkshah@...eaurora.org,
        evgreen@...omium.org, Douglas Anderson <dianders@...omium.org>,
        Alexios Zavras <alexios.zavras@...el.com>,
        Allison Randal <allison@...utok.net>,
        Colin Cross <ccross@...roid.com>,
        Kevin Hilman <khilman@...com>,
        Santosh Shilimkar <santosh.shilimkar@...com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 3/5] kernel/cpu_pm: Fix uninitted local in cpu_pm

cpu_pm_notify() is basically a wrapper of notifier_call_chain().
notifier_call_chain() doesn't initialize *nr_calls to 0 before it
starts incrementing it--presumably it's up to the callers to do this.

Unfortunately the callers of cpu_pm_notify() don't init *nr_calls.
This potentially means you could get too many or two few calls to
CPU_PM_ENTER_FAILED or CPU_CLUSTER_PM_ENTER_FAILED depending on the
luck of the stack.

Let's fix this.

Fixes: ab10023e0088 ("cpu_pm: Add cpu power management notifiers")
Signed-off-by: Douglas Anderson <dianders@...omium.org>
---

Changes in v4: None
Changes in v3: None
Changes in v2:
- ("Fix uninitted local in cpu_pm") new for v2.

 kernel/cpu_pm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c
index cbca6879ab7d..44a259338e33 100644
--- a/kernel/cpu_pm.c
+++ b/kernel/cpu_pm.c
@@ -80,7 +80,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
  */
 int cpu_pm_enter(void)
 {
-	int nr_calls;
+	int nr_calls = 0;
 	int ret = 0;
 
 	ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls);
@@ -131,7 +131,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_exit);
  */
 int cpu_cluster_pm_enter(void)
 {
-	int nr_calls;
+	int nr_calls = 0;
 	int ret = 0;
 
 	ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls);
-- 
2.26.1.301.g55bc3eb7cb9-goog