regmap: Call regmap_debugfs_exit() prior to _init()

From: Fabio Estevam <[email protected]>

Since commit cffa4b2122f5 ("regmap: debugfs: Fix a memory leak when calling regmap_attach_dev"), the following debugfs error is seen on i.MX boards:

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

In the attempt to fix the memory leak, the above commit added a NULL check for map->debugfs_name. For the first debufs entry, map->debugfs_name is NULL and then the new name is allocated via kasprintf().

For the second debugfs entry, map->debugfs_name() is no longer NULL, so it will keep using the old entry name and the duplicate name error is seen.

Quoting Mark Brown:

"That means that if the device gets freed we'll end up with the old debugfs file hanging around pointing at nothing.
...
To be more explicit this means we need a call to regmap_debugfs_exit() which will clean up all the existing debugfs stuff before we loose references to it."

Call regmap_debugfs_exit() prior to regmap_debugfs_init() to fix the problem.

Tested on i.MX6Q and i.MX6SX boards.

---
Changes since v2:
- Use regmap_debugfs_exit() as suggested by Mark.

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

index 21a0c2562ec0..f7811641ed5a 100644
@@ -647,6 +647,7 @@ int regmap_attach_dev(struct device *dev, struct regmap *map,
 	if (ret)
 		return ret;
 
+	regmap_debugfs_exit(map);
 	regmap_debugfs_init(map);
 
 	/* Add a devres resource for dev_get_regmap() */

2.25.1

Applied to

https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git for-next

Thanks!

[1/1] regmap: Call regmap_debugfs_exit() prior to _init()

      commit: 530792efa6cb86f5612ff093333fec735793b582

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

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Thanks,
Mark