All of lore.kernel.org
 help / color / mirror / Atom feed
From: Xiaomeng Tong <xiam0nd.tong@gmail.com>
To: agross@kernel.org
Cc: bjorn.andersson@linaro.org, will@kernel.org,
	mark.rutland@arm.com, nleeder@codeaurora.org,
	linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Xiaomeng Tong <xiam0nd.tong@gmail.com>,
	stable@vger.kernel.org
Subject: [PATCH] perf: qcom_l2_pmu: fix an incorrect NULL check on list iterator
Date: Sun, 27 Mar 2022 13:57:33 +0800	[thread overview]
Message-ID: <20220327055733.4070-1-xiam0nd.tong@gmail.com> (raw)

The bug is here:
	return cluster;

The list iterator value 'cluster' will *always* be set and non-NULL
by list_for_each_entry(), so it is incorrect to assume that the
iterator value will be NULL if the list is empty or no element
is found.

To fix the bug, return 'cluster' when found, otherwise return NULL.

Cc: stable@vger.kernel.org
Fixes: 21bdbb7102ede ("perf: add qcom l2 cache perf events driver")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
---
 drivers/perf/qcom_l2_pmu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/perf/qcom_l2_pmu.c b/drivers/perf/qcom_l2_pmu.c
index 7640491aab12..30234c261b05 100644
--- a/drivers/perf/qcom_l2_pmu.c
+++ b/drivers/perf/qcom_l2_pmu.c
@@ -736,7 +736,7 @@ static struct cluster_pmu *l2_cache_associate_cpu_with_cluster(
 {
 	u64 mpidr;
 	int cpu_cluster_id;
-	struct cluster_pmu *cluster = NULL;
+	struct cluster_pmu *cluster;
 
 	/*
 	 * This assumes that the cluster_id is in MPIDR[aff1] for
@@ -758,10 +758,10 @@ static struct cluster_pmu *l2_cache_associate_cpu_with_cluster(
 			 cluster->cluster_id);
 		cpumask_set_cpu(cpu, &cluster->cluster_cpus);
 		*per_cpu_ptr(l2cache_pmu->pmu_cluster, cpu) = cluster;
-		break;
+		return cluster;
 	}
 
-	return cluster;
+	return NULL;
 }
 
 static int l2cache_pmu_online_cpu(unsigned int cpu, struct hlist_node *node)
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: Xiaomeng Tong <xiam0nd.tong@gmail.com>
To: agross@kernel.org
Cc: bjorn.andersson@linaro.org, will@kernel.org,
	mark.rutland@arm.com, nleeder@codeaurora.org,
	linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Xiaomeng Tong <xiam0nd.tong@gmail.com>,
	stable@vger.kernel.org
Subject: [PATCH] perf: qcom_l2_pmu: fix an incorrect NULL check on list iterator
Date: Sun, 27 Mar 2022 13:57:33 +0800	[thread overview]
Message-ID: <20220327055733.4070-1-xiam0nd.tong@gmail.com> (raw)

The bug is here:
	return cluster;

The list iterator value 'cluster' will *always* be set and non-NULL
by list_for_each_entry(), so it is incorrect to assume that the
iterator value will be NULL if the list is empty or no element
is found.

To fix the bug, return 'cluster' when found, otherwise return NULL.

Cc: stable@vger.kernel.org
Fixes: 21bdbb7102ede ("perf: add qcom l2 cache perf events driver")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
---
 drivers/perf/qcom_l2_pmu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/perf/qcom_l2_pmu.c b/drivers/perf/qcom_l2_pmu.c
index 7640491aab12..30234c261b05 100644
--- a/drivers/perf/qcom_l2_pmu.c
+++ b/drivers/perf/qcom_l2_pmu.c
@@ -736,7 +736,7 @@ static struct cluster_pmu *l2_cache_associate_cpu_with_cluster(
 {
 	u64 mpidr;
 	int cpu_cluster_id;
-	struct cluster_pmu *cluster = NULL;
+	struct cluster_pmu *cluster;
 
 	/*
 	 * This assumes that the cluster_id is in MPIDR[aff1] for
@@ -758,10 +758,10 @@ static struct cluster_pmu *l2_cache_associate_cpu_with_cluster(
 			 cluster->cluster_id);
 		cpumask_set_cpu(cpu, &cluster->cluster_cpus);
 		*per_cpu_ptr(l2cache_pmu->pmu_cluster, cpu) = cluster;
-		break;
+		return cluster;
 	}
 
-	return cluster;
+	return NULL;
 }
 
 static int l2cache_pmu_online_cpu(unsigned int cpu, struct hlist_node *node)
-- 
2.17.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

             reply	other threads:[~2022-03-27  5:57 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-27  5:57 Xiaomeng Tong [this message]
2022-03-27  5:57 ` [PATCH] perf: qcom_l2_pmu: fix an incorrect NULL check on list iterator Xiaomeng Tong
2022-04-04 10:10 ` Will Deacon
2022-04-04 10:10   ` Will Deacon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220327055733.4070-1-xiam0nd.tong@gmail.com \
    --to=xiam0nd.tong@gmail.com \
    --cc=agross@kernel.org \
    --cc=bjorn.andersson@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=nleeder@codeaurora.org \
    --cc=stable@vger.kernel.org \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.