linux-kernel - [PATCH] regmap: debugfs: fix a memory leak when calling regmap_attach

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Message-Id: <20201225122613.3810458-1-xiaolei.wang@windriver.com>
Date:   Fri, 25 Dec 2020 20:26:13 +0800
From:   Xiaolei Wang <xiaolei.wang@...driver.com>
To:     broonie@...nel.org
Cc:     gregkh@...uxfoundation.org, rafael@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] regmap: debugfs: fix a memory leak when calling regmap_attach_dev

This should be caused by
commit <9b947a13e7f6> ("<regmap: use debugfs even when no device>")

After initializing the regmap through
syscon_regmap_lookup_by_compatible, then regmap_attach_dev to the
device, because the debugfs_name has been allocated, there is no need to
redistribute it again

unreferenced object 0xd8399b80 (size 64):
  comm "swapper/0", pid 1, jiffies 4294937641 (age 278.590s)
  hex dump (first 32 bytes):
	64 75 6d 6d 79 2d 69 6f 6d 75 78 63 2d 67 70 72
dummy-iomuxc-gpr
	40 32 30 65 34 30 30 30 00 7f 52 5b d8 7e 42 69
@20e4000..R[.~Bi
  backtrace:
	[<ca384d6f>] kasprintf+0x2c/0x54
	[<6ad3bbc2>] regmap_debugfs_init+0xdc/0x2fc
	[<bc4181da>] __regmap_init+0xc38/0xd88
	[<1f7e0609>] of_syscon_register+0x168/0x294
	[<735e8766>] device_node_get_regmap+0x6c/0x98
	[<d96c8982>] imx6ul_init_machine+0x20/0x88
	[<0456565b>] customize_machine+0x1c/0x30
	[<d07393d8>] do_one_initcall+0x80/0x3ac
	[<7e584867>] kernel_init_freeable+0x170/0x1f0
	[<80074741>] kernel_init+0x8/0x120
	[<285d6f28>] ret_from_fork+0x14/0x20
	[<00000000>] 0x0

Signed-off-by: Xiaolei Wang <xiaolei.wang@...driver.com>
---
 drivers/base/regmap/regmap-debugfs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 8dfac7f3ed7a..271142981f98 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -582,8 +582,10 @@ void regmap_debugfs_init(struct regmap *map)
 		devname = dev_name(map->dev);
 
 	if (name) {
-		map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
+		if (!map->debugfs_name) {
+			map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 					      devname, name);
+		}
 		name = map->debugfs_name;
 	} else {
 		name = devname;
-- 
2.25.1