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    Subject[PATCH AUTOSEL 4.9 09/45] memstick: Fix error cleanup path of memstick_init
    Date
    From: Wang Hai <wanghai26@huawei.com>

    [ 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
    entry_SYSCALL_64_after_hwframe+0x49/0xbe

    Fixes: baf8532a147d ("memstick: initial commit for Sony MemoryStick support")
    Reported-by: Hulk Robot <hulkci@huawei.com>
    Signed-off-by: Wang Hai <wanghai26@huawei.com>
    Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    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 4d673a626db4..1041eb7a6167 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;
    --
    2.20.1
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