[PATCH AUTOSEL 4.19 009/158] regmap: debugfs: Fix memory leak in regmap_debugfs_init

Sasha Levin
2019-07-15T14:59:49Z

From: Daniel Baluta <daniel.baluta@nxp.com>

[ Upstream commit 2899872b627e99b7586fe3b6c9f861da1b4d5072 ]

As detected by kmemleak running on i.MX6ULL board:

nreferenced object 0xd8366600 (size 64):
comm "swapper/0", pid 1, jiffies 4294937370 (age 933.220s)
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 e3 f3 ab fe d1 1b dd @20e4000........
backtrace:
[<b0402aec>] kasprintf+0x2c/0x54
[<a6fbad2c>] regmap_debugfs_init+0x7c/0x31c
[<9c8d91fa>] __regmap_init+0xb5c/0xcf4
[<5b1c3d2a>] of_syscon_register+0x164/0x2c4
[<596a5d80>] syscon_node_to_regmap+0x64/0x90
[<49bd597b>] imx6ul_init_machine+0x34/0xa0
[<250a4dac>] customize_machine+0x1c/0x30
[<2d19fdaf>] do_one_initcall+0x7c/0x398
[<e6084469>] kernel_init_freeable+0x328/0x448
[<168c9101>] kernel_init+0x8/0x114
[<913268aa>] ret_from_fork+0x14/0x20
[<ce7b131a>] 0x0

Root cause is that map->debugfs_name is allocated using kasprintf
and then the pointer is lost by assigning it other memory address.

Reported-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 87b562e49a43..c9687c8b2347 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -575,6 +575,8 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
}

if (!strcmp(name, "dummy")) {
+ kfree(map->debugfs_name);
+
map->debugfs_name = kasprintf(GFP_KERNEL, "dummy%d",
dummy_index);
name = map->debugfs_name;
--
2.20.1