Dinghao Liu wrote:
> Resources allocated by kcalloc() in btt_freelist_init(),
> btt_rtt_init(), and btt_maplocks_init() are not correctly
> released in their callers when an error happens. For
> example, when an error happens in btt_freelist_init(), its
> caller discover_arenas() will directly free arena, which makes
> arena->freelist a leaked memory. Fix these memleaks by using
> devm_kcalloc() to make the memory auto-freed on driver detach.
Thanks for this work!
>
> Fixes: 5212e11fde4d ("nd_btt: atomic sector updates")
> Signed-off-by: Dinghao Liu <dinghao....@zju.edu.cn>
> ---
>
> Changelog:
>
> v2: -Use devm_kcalloc() to fix the memleaks.
> -Fix the potential leaked memory in btt_rtt_init()
> and btt_maplocks_init().
> ---
> drivers/nvdimm/btt.c | 35 ++++++++++++++++-------------------
> 1 file changed, 16 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
> index d5593b0dc700..c55231f42617 100644
> --- a/drivers/nvdimm/btt.c
> +++ b/drivers/nvdimm/btt.c
> @@ -531,13 +531,13 @@ static int arena_clear_freelist_error(struct arena_info
> *arena, u32 lane)
> return ret;
> }
>
> -static int btt_freelist_init(struct arena_info *arena)
> +static int btt_freelist_init(struct device *dev, struct arena_info *arena)
Both struct arena_info and struct btt contain references to struct nd_btt
which is the device you are passing down this call stack.
Just use the device in the arena/btt rather than passing a device
structure. That makes the code easier to read and ensures that the device
associated with this arena or btt is used.
> {
> int new, ret;
> struct log_entry log_new;
> u32 i, map_entry, log_oldmap, log_newmap;
>
> - arena->freelist = kcalloc(arena->nfree, sizeof(struct free_entry),
> + arena->freelist = devm_kcalloc(dev, arena->nfree, sizeof(struct
> free_entry),
... devm_kcalloc(&arena->nd_btt.dev, ...)
> GFP_KERNEL);
> if (!arena->freelist)
> return -ENOMEM;
> @@ -718,20 +718,20 @@ static int log_set_indices(struct arena_info *arena)
> return 0;
> }
>
> -static int btt_rtt_init(struct arena_info *arena)
> +static int btt_rtt_init(struct device *dev, struct arena_info *arena)
> {
> - arena->rtt = kcalloc(arena->nfree, sizeof(u32), GFP_KERNEL);
> + arena->rtt = devm_kcalloc(dev, arena->nfree, sizeof(u32), GFP_KERNEL);
> if (arena->rtt == NULL)
> return -ENOMEM;
>
> return 0;
> }
>
> -static int btt_maplocks_init(struct arena_info *arena)
> +static int btt_maplocks_init(struct device *dev, struct arena_info *arena)
> {
> u32 i;
>
> - arena->map_locks = kcalloc(arena->nfree, sizeof(struct aligned_lock),
> + arena->map_locks = devm_kcalloc(dev, arena->nfree, sizeof(struct
> aligned_lock),
> GFP_KERNEL);
> if (!arena->map_locks)
> return -ENOMEM;
> @@ -805,9 +805,6 @@ static void free_arenas(struct btt *btt)
>
> list_for_each_entry_safe(arena, next, &btt->arena_list, list) {
> list_del(&arena->list);
> - kfree(arena->rtt);
> - kfree(arena->map_locks);
> - kfree(arena->freelist);
This does not quite work.
free_arenas() is used in the error paths of create_arenas() and
discover_arenas(). In those cases devm_kfree() is probably a better way
to clean up this.
However...
> debugfs_remove_recursive(arena->debugfs_dir);
> kfree(arena);
Why can't arena be allocated with devm_*?
We need to change this up a bit more to handle the error path vs regular
device shutdown free (automatic devm frees).
Ira
