[PATCH AUTOSEL 4.14 11/60] memstick: Fix error cleanup path of memstick_init

From: Sasha Levin
Date: Fri Jul 19 2019 - 00:22:11 EST

From: Wang Hai <wanghai26@xxxxxxxxxx>

[ Upstream commit 65f1a0d39c289bb6fc85635528cd36c4b07f560e ]

If bus_register fails. On its error handling path, it has cleaned up
what it has done. There is no need to call bus_unregister again.
Otherwise, if bus_unregister is called, issues such as null-ptr-deref
will arise.

Syzkaller report this:

kobject_add_internal failed for memstick (error: -12 parent: bus)
BUG: KASAN: null-ptr-deref in sysfs_remove_file_ns+0x1b/0x40 fs/sysfs/file.c:467
Read of size 8 at addr 0000000000000078 by task syz-executor.0/4460

Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xa9/0x10e lib/dump_stack.c:113
__kasan_report+0x171/0x18d mm/kasan/report.c:321
kasan_report+0xe/0x20 mm/kasan/common.c:614
sysfs_remove_file_ns+0x1b/0x40 fs/sysfs/file.c:467
sysfs_remove_file include/linux/sysfs.h:519 [inline]
bus_remove_file+0x6c/0x90 drivers/base/bus.c:145
remove_probe_files drivers/base/bus.c:599 [inline]
bus_unregister+0x6e/0x100 drivers/base/bus.c:916 ? 0xffffffffc1590000
memstick_init+0x7a/0x1000 [memstick]
do_one_initcall+0xb9/0x3b5 init/main.c:914
do_init_module+0xe0/0x330 kernel/module.c:3468
load_module+0x38eb/0x4270 kernel/module.c:3819
__do_sys_finit_module+0x162/0x190 kernel/module.c:3909
do_syscall_64+0x72/0x2a0 arch/x86/entry/common.c:298

Fixes: baf8532a147d ("memstick: initial commit for Sony MemoryStick support")
Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Signed-off-by: Wang Hai <wanghai26@xxxxxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/memstick/core/memstick.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/memstick/core/memstick.c b/drivers/memstick/core/memstick.c
index 1246d69ba187..b1564cacd19e 100644
--- a/drivers/memstick/core/memstick.c
+++ b/drivers/memstick/core/memstick.c
@@ -629,13 +629,18 @@ static int __init memstick_init(void)
return -ENOMEM;

rc = bus_register(&memstick_bus_type);
- if (!rc)
- rc = class_register(&memstick_host_class);
+ if (rc)
+ goto error_destroy_workqueue;

- if (!rc)
- return 0;
+ rc = class_register(&memstick_host_class);
+ if (rc)
+ goto error_bus_unregister;
+ return 0;


return rc;