[PATCH 6.6 235/737] regulator: core: Protect regulator_supply_alias_list with regulator_list_mutex

6.6-stable review patch. If anyone has any objections, please let me know.

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From: sparkhuang huangshaobo3@xiaomi.com

[ Upstream commit 0cc15a10c3b4ab14cd71b779fd5c9ca0cb2bc30d ]

regulator_supply_alias_list was accessed without any locking in regulator_supply_alias(), regulator_register_supply_alias(), and regulator_unregister_supply_alias(). Concurrent registration, unregistration and lookups can race, leading to:

1 use-after-free if an alias entry is removed while being read, 2 duplicate entries when two threads register the same alias, 3 inconsistent alias mappings observed by consumers.

Protect all traversals, insertions and deletions on regulator_supply_alias_list with the existing regulator_list_mutex.

Fixes: a06ccd9c3785f ("regulator: core: Add ability to create a lookup alias for supply") Signed-off-by: sparkhuang huangshaobo3@xiaomi.com Reviewed-by: Charles Keepax ckeepax@opensource.cirrus.com Link: https://patch.msgid.link/20251127025716.5440-1-huangshaobo3@xiaomi.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/regulator/core.c | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 465f4f870162f..23cdf220ca7db 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1970,6 +1970,7 @@ static void regulator_supply_alias(struct device **dev, const char **supply) { struct regulator_supply_alias *map;

+ mutex_lock(&regulator_list_mutex); map = regulator_find_supply_alias(*dev, *supply); if (map) { dev_dbg(*dev, "Mapping supply %s to %s,%s\n", @@ -1978,6 +1979,7 @@ static void regulator_supply_alias(struct device **dev, const char **supply) *dev = map->alias_dev; *supply = map->alias_supply; } + mutex_unlock(&regulator_list_mutex); }

static int regulator_match(struct device *dev, const void *data) @@ -2456,22 +2458,26 @@ int regulator_register_supply_alias(struct device *dev, const char *id, const char *alias_id) { struct regulator_supply_alias *map; + struct regulator_supply_alias *new_map;

- map = regulator_find_supply_alias(dev, id); - if (map) - return -EEXIST; - - map = kzalloc(sizeof(struct regulator_supply_alias), GFP_KERNEL); - if (!map) + new_map = kzalloc(sizeof(struct regulator_supply_alias), GFP_KERNEL); + if (!new_map) return -ENOMEM;

- map->src_dev = dev; - map->src_supply = id; - map->alias_dev = alias_dev; - map->alias_supply = alias_id; - - list_add(&map->list, &regulator_supply_alias_list); + mutex_lock(&regulator_list_mutex); + map = regulator_find_supply_alias(dev, id); + if (map) { + mutex_unlock(&regulator_list_mutex); + kfree(new_map); + return -EEXIST; + }

+ new_map->src_dev = dev; + new_map->src_supply = id; + new_map->alias_dev = alias_dev; + new_map->alias_supply = alias_id; + list_add(&new_map->list, &regulator_supply_alias_list); + mutex_unlock(&regulator_list_mutex); pr_info("Adding alias for supply %s,%s -> %s,%s\n", id, dev_name(dev), alias_id, dev_name(alias_dev));

@@ -2491,11 +2497,13 @@ void regulator_unregister_supply_alias(struct device *dev, const char *id) { struct regulator_supply_alias *map;

+ mutex_lock(&regulator_list_mutex); map = regulator_find_supply_alias(dev, id); if (map) { list_del(&map->list); kfree(map); } + mutex_unlock(&regulator_list_mutex); } EXPORT_SYMBOL_GPL(regulator_unregister_supply_alias);