[PATCH 4.4 62/92] mtd: Check add_mtd_device() ret code

Greg Kroah-Hartman
2019-12-04T17:59:41Z

From: Boris Brezillon <bbrezillon@kernel.org>

[ Upstream commit 2b6f0090a3335b7bdd03ca520c35591159463041 ]

add_mtd_device() can fail. We should always check its return value
and gracefully handle the failure case. Fix the call sites where this
not done (in mtdpart.c) and add a __must_check attribute to the
prototype to avoid this kind of mistakes.

Signed-off-by: Boris Brezillon <bbrezillon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/mtd/mtdcore.h | 2 +-
drivers/mtd/mtdpart.c | 36 +++++++++++++++++++++++++++++++-----
2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/mtdcore.h b/drivers/mtd/mtdcore.h
index 7b0353399a106..b837f44716820 100644
--- a/drivers/mtd/mtdcore.h
+++ b/drivers/mtd/mtdcore.h
@@ -6,7 +6,7 @@
extern struct mutex mtd_table_mutex;

struct mtd_info *__mtd_next_device(int i);
-int add_mtd_device(struct mtd_info *mtd);
+int __must_check add_mtd_device(struct mtd_info *mtd);
int del_mtd_device(struct mtd_info *mtd);
int add_mtd_partitions(struct mtd_info *, const struct mtd_partition *, int);
int del_mtd_partitions(struct mtd_info *);
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index f8ba153f63bfe..9b48be05cd1af 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -610,10 +610,22 @@ int mtd_add_partition(struct mtd_info *master, const char *name,
list_add(&new->list, &mtd_partitions);
mutex_unlock(&mtd_partitions_mutex);

- add_mtd_device(&new->mtd);
+ ret = add_mtd_device(&new->mtd);
+ if (ret)
+ goto err_remove_part;

mtd_add_partition_attrs(new);

+ return 0;
+
+err_remove_part:
+ mutex_lock(&mtd_partitions_mutex);
+ list_del(&new->list);
+ mutex_unlock(&mtd_partitions_mutex);
+
+ free_partition(new);
+ pr_info("%s:%i\n", __func__, __LINE__);
+
return ret;
}
EXPORT_SYMBOL_GPL(mtd_add_partition);
@@ -658,28 +670,42 @@ int add_mtd_partitions(struct mtd_info *master,
{
struct mtd_part *slave;
uint64_t cur_offset = 0;
- int i;
+ int i, ret;

printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);

for (i = 0; i < nbparts; i++) {
slave = allocate_partition(master, parts + i, i, cur_offset);
if (IS_ERR(slave)) {
- del_mtd_partitions(master);
- return PTR_ERR(slave);
+ ret = PTR_ERR(slave);
+ goto err_del_partitions;
}

mutex_lock(&mtd_partitions_mutex);
list_add(&slave->list, &mtd_partitions);
mutex_unlock(&mtd_partitions_mutex);

- add_mtd_device(&slave->mtd);
+ ret = add_mtd_device(&slave->mtd);
+ if (ret) {
+ mutex_lock(&mtd_partitions_mutex);
+ list_del(&slave->list);
+ mutex_unlock(&mtd_partitions_mutex);
+
+ free_partition(slave);
+ goto err_del_partitions;
+ }
+
mtd_add_partition_attrs(slave);

cur_offset = slave->offset + slave->mtd.size;
}

return 0;
+
+err_del_partitions:
+ del_mtd_partitions(master);
+
+ return ret;
}

static DEFINE_SPINLOCK(part_parser_lock);
--
2.20.1