On Wed, 15 May 2019 at 16:39, Wang Hai <wanghai26@xxxxxxxxxx> wrote:
>
> 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
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> Fixes: baf8532a147d ("memstick: initial commit for Sony MemoryStick support")
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Wang Hai <wanghai26@xxxxxxxxxx>
Applied for next, thanks!
Kind regards
Uffe
> ---
> 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;
>
> +error_bus_unregister:
> bus_unregister(&memstick_bus_type);
> +error_destroy_workqueue:
> destroy_workqueue(workqueue);
>
> return rc;
> --
> 2.17.1
>
>
