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From:   Georgi Djakov <georgi.djakov@linaro.org>
To:     linux-pm@vger.kernel.org, evgreen@chromium.org,
        daidavid1@codeaurora.org
Cc:     vincent.guittot@linaro.org, bjorn.andersson@linaro.org,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        Georgi Djakov <georgi.djakov@linaro.org>
Subject: [PATCH] interconnect: Add locking in icc_set_tag()
Date:   Fri, 18 Oct 2019 17:17:50 +0300
Message-Id: <20191018141750.17032-1-georgi.djakov@linaro.org>
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Sender: linux-kernel-owner@vger.kernel.org
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We must ensure that the tag is not changed while we aggregate the
requests. Currently the icc_set_tag() is not using any locks and this
may cause the values to be aggregated incorrectly. Fix this by acquiring
the icc_lock while we set the tag.

Fixes: 127ab2cc5f19 ("interconnect: Add support for path tags")
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
---
 drivers/interconnect/core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index e24092558c29..4940c0741d40 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -408,8 +408,12 @@ void icc_set_tag(struct icc_path *path, u32 tag)
 	if (!path)
 		return;
 
+	mutex_lock(&icc_lock);
+
 	for (i = 0; i < path->num_nodes; i++)
 		path->reqs[i].tag = tag;
+
+	mutex_unlock(&icc_lock);
 }
 EXPORT_SYMBOL_GPL(icc_set_tag);