linux-kernel - [PATCH v2 2/2] of: overlay: Fix cleanup order in of_overlay

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Date:   Mon,  4 Dec 2017 16:47:36 +0100
From:   Geert Uytterhoeven <geert+renesas@...der.be>
To:     Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>
Cc:     Colin King <colin.king@...onical.com>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Geert Uytterhoeven <geert+renesas@...der.be>
Subject: [PATCH v2 2/2] of: overlay: Fix cleanup order in of_overlay_apply()

The special overlay mutex is taken first, hence it should be released
last in the error path.

Move "mutex_lock(&of_mutex)" up, as suggested by Frank, as
free_overlay_changeset() should be called with that mutex held if any
non-trivial cleanup is to be done.

Merge the two tail statements of the success and error paths, now they
became identical.

Fixes: f948d6d8b792bb90 ("of: overlay: avoid race condition between applying multiple overlays")
Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
---
This is v2 of commit bd80e2555c5c9d45 ("of: overlay: Fix cleanup order
in of_overlay_apply()"), which was dropped by Rob.
---
 drivers/of/overlay.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 312cd658bec0083b..0ddb7748ac85498f 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -705,12 +705,11 @@ int of_overlay_apply(struct device_node *tree, int *ovcs_id)
 	}
 
 	of_overlay_mutex_lock();
+	mutex_lock(&of_mutex);
 
 	ret = of_resolve_phandles(tree);
 	if (ret)
-		goto err_overlay_unlock;
-
-	mutex_lock(&of_mutex);
+		goto err_free_overlay_changeset;
 
 	ret = init_overlay_changeset(ovcs, tree);
 	if (ret)
@@ -754,17 +753,13 @@ int of_overlay_apply(struct device_node *tree, int *ovcs_id)
 			ret = ret_tmp;
 	}
 
-	mutex_unlock(&of_mutex);
-	of_overlay_mutex_unlock();
-
-	goto out;
+	goto out_unlock;
 
 err_free_overlay_changeset:
 	free_overlay_changeset(ovcs);
 
+out_unlock:
 	mutex_unlock(&of_mutex);
-
-err_overlay_unlock:
 	of_overlay_mutex_unlock();
 
 out:
-- 
2.7.4