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| author | Zxyan Zhu <zxyan0222@gmail.com> | 2026-04-09 06:50:15 +0300 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2026-04-09 22:50:54 +0300 |
| commit | 7d696210cf36ed31c7c37f6eff17cb7147e83367 (patch) | |
| tree | 2cec19e062225555b9aa3a6756a81fe1687a004b | |
| parent | 1ef3e1c278eb7bda1cc09a508c3fe65d2e567c77 (diff) | |
| download | linux-7d696210cf36ed31c7c37f6eff17cb7147e83367.tar.xz | |
regmap: debugfs: fix race condition in dummy name allocation
Use IDA instead of a simple counter for generating unique dummy names.
The previous implementation used dummy_index++ which is not atomic,
leading to potential duplicate names when multiple threads call
regmap_debugfs_init() concurrently with name="dummy".
Signed-off-by: Zxyan Zhu <zxyan0222@gmail.com>
Link: https://patch.msgid.link/20260409035015.950764-1-zxyan0222@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | drivers/base/regmap/internal.h | 1 | ||||
| -rw-r--r-- | drivers/base/regmap/regmap-debugfs.c | 21 |
2 files changed, 17 insertions, 5 deletions
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h index c77f3a49a89e..55273a6178f8 100644 --- a/drivers/base/regmap/internal.h +++ b/drivers/base/regmap/internal.h @@ -84,6 +84,7 @@ struct regmap { bool debugfs_disable; struct dentry *debugfs; const char *debugfs_name; + int debugfs_dummy_id; unsigned int debugfs_reg_len; unsigned int debugfs_val_len; diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index 5a46ce5fee72..18f1c60749fe 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -12,6 +12,7 @@ #include <linux/uaccess.h> #include <linux/device.h> #include <linux/list.h> +#include <linux/idr.h> #include "internal.h" @@ -20,7 +21,7 @@ struct regmap_debugfs_node { struct list_head link; }; -static unsigned int dummy_index; +static DEFINE_IDA(dummy_ida); static struct dentry *regmap_debugfs_root; static LIST_HEAD(regmap_debugfs_early_list); static DEFINE_MUTEX(regmap_debugfs_early_lock); @@ -539,6 +540,7 @@ void regmap_debugfs_init(struct regmap *map) struct regmap_range_node *range_node; const char *devname = "dummy"; const char *name = map->name; + int id; /* * Userspace can initiate reads from the hardware over debugfs. @@ -567,6 +569,7 @@ void regmap_debugfs_init(struct regmap *map) INIT_LIST_HEAD(&map->debugfs_off_cache); mutex_init(&map->cache_lock); + map->debugfs_dummy_id = -1; if (map->dev) devname = dev_name(map->dev); @@ -585,12 +588,16 @@ void regmap_debugfs_init(struct regmap *map) if (!strcmp(name, "dummy")) { kfree(map->debugfs_name); - map->debugfs_name = kasprintf(GFP_KERNEL, "dummy%d", - dummy_index); - if (!map->debugfs_name) + id = ida_alloc(&dummy_ida, GFP_KERNEL); + if (id < 0) return; + map->debugfs_name = kasprintf(GFP_KERNEL, "dummy%d", id); + if (!map->debugfs_name) { + ida_free(&dummy_ida, id); + return; + } + map->debugfs_dummy_id = id; name = map->debugfs_name; - dummy_index++; } map->debugfs = debugfs_create_dir(name, regmap_debugfs_root); @@ -660,6 +667,10 @@ void regmap_debugfs_exit(struct regmap *map) mutex_lock(&map->cache_lock); regmap_debugfs_free_dump_cache(map); mutex_unlock(&map->cache_lock); + if (map->debugfs_dummy_id >= 0) { + ida_free(&dummy_ida, map->debugfs_dummy_id); + map->debugfs_dummy_id = -1; + } kfree(map->debugfs_name); map->debugfs_name = NULL; } else { |