From:   Fabio Estevam <festevam@gmail.com>
To:     broonie@kernel.org
Cc:     matthias.schiffer@ew.tq-group.com, linux-kernel@vger.kernel.org,
        Fabio Estevam <festevam@gmail.com>
Subject: [PATCH] regmap: debugfs: Free the previous allocated debugfs_name buffer
Date:   Thu,  6 Jan 2022 14:15:37 -0300
Message-Id: <20220106171537.3091643-1-festevam@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The following error message is seen when booting an imx6q-sabresd:

debugfs: Directory 'dummy-iomuxc-gpr@20e0000' with parent 'regmap' already present!

By inspecting the duplicate directory name: 

[    0.274418] platform panel: Fixing up cyclic dependency with ldb
[    0.276896] ************ 1: devname is dummy
[    0.276926] ************ 2: name is iomuxc-gpr@20e0000
[    0.276951] ************ 3: Forming the final name
[    0.276979] ************ 3a: Name from map->debugfs_name dummy-iomuxc-gpr@20e0000
[    0.277001] ************ 4: name is dummy-iomuxc-gpr@20e0000
[    0.277022] ************ 5: Final name is dummy-iomuxc-gpr@20e0000
[    0.277746] No ATAGs?
[    0.278355] hw-breakpoint: found 5 (+1 reserved) breakpoint and 1 watchpoint registers.
[    0.278469] hw-breakpoint: maximum watchpoint size is 4 bytes.
[    0.282007] ********** gpr succeeded
[    0.282042] ************ 1: devname is 20e0000.pinctrl
[    0.282070] ************ 2: name is gpr
[    0.282093] ************ 3a: Name from map->debugfs_name dummy-iomuxc-gpr@20e0000
[    0.282115] ************ 4: name is dummy-iomuxc-gpr@20e0000
[    0.282138] ************ 5: Final name is dummy-iomuxc-gpr@20e0000
[    0.282185] debugfs: Directory 'dummy-iomuxc-gpr@20e0000' with parent 'regmap' already present!


The 'dummy-iomuxc-gpr@20e0000' name is caused by a non-freed map->debugfs_name
buffer.

After calling kfree(map->debugfs_name), no more duplicate naming is seen:

After:

[    0.257135] platform 2800000.ipu: Fixing up cyclic dependency with 120000.hdmi
[    0.257460] platform 2800000.ipu: Fixing up cyclic dependency with 20e0000.iomuxc-gpr:ipu2_csi1_mux
[    0.257782] platform 2800000.ipu: Fixing up cyclic dependency with 21dc000.mipi
[    0.273536] platform panel: Fixing up cyclic dependency with ldb
[    0.276013] ************ 1: devname is dummy
[    0.276043] ************ 2: name is iomuxc-gpr@20e0000
[    0.276067] ************ 3: Forming the final name
[    0.276097] ************ 3a: Name from map->debugfs_name dummy-iomuxc-gpr@20e0000
[    0.276119] ************ 4: name is dummy-iomuxc-gpr@20e0000
[    0.276141] ************ 5: Final name is dummy-iomuxc-gpr@20e0000
[    0.276859] No ATAGs?
[    0.277468] hw-breakpoint: found 5 (+1 reserved) breakpoint and 1 watchpoint registers.
[    0.277580] hw-breakpoint: maximum watchpoint size is 4 bytes.
[    0.281122] ********** gpr succeeded
[    0.281156] ************ 1: devname is 20e0000.pinctrl
[    0.281184] ************ 2: name is gpr
[    0.281206] ************ 3a: Name from map->debugfs_name 20e0000.pinctrl
[    0.281228] ************ 4: name is 20e0000.pinctrl
[    0.281251] ************ 5: Final name is 20e0000.pinctrl

Signed-off-by: Fabio Estevam <festevam@gmail.com>
---
 drivers/base/regmap/regmap-debugfs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index ad684d37c2da..18f0c7223082 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -589,6 +589,7 @@ void regmap_debugfs_init(struct regmap *map)
 				return;
 		}
 		name = map->debugfs_name;
+		kfree(map->debugfs_name);
 	} else {
 		name = devname;
 	}
@@ -600,6 +601,7 @@ void regmap_debugfs_init(struct regmap *map)
 		if (!map->debugfs_name)
 				return;
 		name = map->debugfs_name;
+		kfree(map->debugfs_name);
 		dummy_index++;
 	}
 
-- 
2.25.1