linux-kernel - [PATCH] regmap: fix potential memory leak of regmap

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Message-ID: <20250626172823.18725-1-abdun.nihaal@gmail.com>
Date: Thu, 26 Jun 2025 22:58:21 +0530
From: Abdun Nihaal <abdun.nihaal@...il.com>
To: broonie@...nel.org
Cc: Abdun Nihaal <abdun.nihaal@...il.com>,
	gregkh@...uxfoundation.org,
	rafael@...nel.org,
	dakr@...nel.org,
	tanureal@...nsource.cirrus.com,
	linux-kernel@...r.kernel.org
Subject: [PATCH] regmap: fix potential memory leak of regmap_bus

When __regmap_init() is called from __regmap_init_i2c() and
__regmap_init_spi() (and their devm versions), the bus argument
obtained from regmap_get_i2c_bus() and regmap_get_spi_bus(), may be
allocated using kmemdup() to support quirks. In those cases, the
bus->free_on_exit field is set to true.

However, inside __regmap_init(), buf is not freed on any error path.
This could lead to a memory leak of regmap_bus when __regmap_init()
fails. Fix that by freeing bus on error path when free_on_exit is set.

Fixes: ea030ca68819 ("regmap-i2c: Set regmap max raw r/w from quirks")
Signed-off-by: Abdun Nihaal <abdun.nihaal@...il.com>
---
This patch is compile tested only. Not tested on real hardware.
Bug was found using our prototype static analysis tool.

 drivers/base/regmap/regmap.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index f2843f814675..1f3f782a04ba 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1173,6 +1173,8 @@ struct regmap *__regmap_init(struct device *dev,
 err_map:
 	kfree(map);
 err:
+	if (bus && bus->free_on_exit)
+		kfree(bus);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(__regmap_init);
-- 
2.43.0