mtd: Fix device name leak when register device failed in add_mtd_device()

There is a kmemleak when register device failed:
  unreferenced object 0xffff888101aab550 (size 8):
    comm "insmod", pid 3922, jiffies 4295277753 (age 925.408s)
    hex dump (first 8 bytes):
      6d 74 64 30 00 88 ff ff                          mtd0....
    backtrace:
      [<00000000bde26724>] __kmalloc_node_track_caller+0x4e/0x150
      [<000000003c32b416>] kvasprintf+0xb0/0x130
      [<000000001f7a8f15>] kobject_set_name_vargs+0x2f/0xb0
      [<000000006e781163>] dev_set_name+0xab/0xe0
      [<00000000e30d0c78>] add_mtd_device+0x4bb/0x700
      [<00000000f3d34de7>] mtd_device_parse_register+0x2ac/0x3f0
      [<00000000c0d88488>] 0xffffffffa0238457
      [<00000000b40d0922>] 0xffffffffa02a008f
      [<0000000023d17b9d>] do_one_initcall+0x87/0x2a0
      [<00000000770f6ca6>] do_init_module+0xdf/0x320
      [<000000007b6768fe>] load_module+0x2f98/0x3330
      [<00000000346bed5a>] __do_sys_finit_module+0x113/0x1b0
      [<00000000674c2290>] do_syscall_64+0x35/0x80
      [<000000004c6a8d97>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

If register device failed, should call put_device() to give up the
reference.

Fixes: 1f24b5a8ecbb ("[MTD] driver model updates")
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20221022121352.2534682-1-zhangxiaoxu5@huawei.com

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 20fcedc3021e3adaf699d9f404a159b99cf29943..756fd27f4cfeef791e8016211d002e256c8865ea 100644 (file)
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -715,8 +715,10 @@ int add_mtd_device(struct mtd_info *mtd)
        mtd_check_of_node(mtd);
        of_node_get(mtd_get_of_node(mtd));
        error = device_register(&mtd->dev);
-       if (error)
+       if (error) {
+               put_device(&mtd->dev);
                goto fail_added;
+       }
 
        /* Add the nvmem provider */
        error = mtd_nvmem_add(mtd);