In the Linux kernel, the following vulnerability has been resolved:
mmc: sdio: fix possible resource leaks in some error paths
If sdio_add_func() or sdio_init_func() fails, sdio_remove_func() can not release the resources, because the sdio function is not presented in these two cases, it won't call of_node_put() or put_device().
To fix these leaks, make sdio_func_present() only control whether device_del() needs to be called or not, then always call of_node_put() and put_device().
In error case in sdio_init_func(), the reference of 'card->dev' is not get, to avoid redundant put in sdio_free_func_cis(), move the get_device() to sdio_alloc_func() and put_device() to sdio_release_func(), it can keep the get/put function be balanced.
Without this patch, while doing fault inject test, it can get the following leak reports, after this fix, the leak is gone.
unreferenced object 0xffff888112514000 (size 2048): comm "kworker/3:2", pid 65, jiffies 4294741614 (age 124.774s) hex dump (first 32 bytes): 00 e0 6f 12 81 88 ff ff 60 58 8d 06 81 88 ff ff ..o.....`X...... 10 40 51 12 81 88 ff ff 10 40 51 12 81 88 ff ff .@Q......@Q..... backtrace: [<000000009e5931da>] kmalloc_trace+0x21/0x110 [<000000002f839ccb>] mmc_alloc_card+0x38/0xb0 [mmc_core] [<0000000004adcbf6>] mmc_sdio_init_card+0xde/0x170 [mmc_core] [<000000007538fea0>] mmc_attach_sdio+0xcb/0x1b0 [mmc_core] [<00000000d4fdeba7>] mmc_rescan+0x54a/0x640 [mmc_core]
unreferenced object 0xffff888112511000 (size 2048): comm "kworker/3:2", pid 65, jiffies 4294741623 (age 124.766s) hex dump (first 32 bytes): 00 40 51 12 81 88 ff ff e0 58 8d 06 81 88 ff ff [email protected]...... 10 10 51 12 81 88 ff ff 10 10 51 12 81 88 ff ff ..Q.......Q..... backtrace: [<000000009e5931da>] kmalloc_trace+0x21/0x110 [<00000000fcbe706c>] sdio_alloc_func+0x35/0x100 [mmc_core] [<00000000c68f4b50>] mmc_attach_sdio.cold.18+0xb1/0x395 [mmc_core] [<00000000d4fdeba7>] mmc_rescan+0x54a/0x640 [mmc_core]