• Yang Yang's avatar
    futex: Move futex_init() to core_initcall · dcc9b826
    Yang Yang authored
    commit 25f71d1c upstream.
    
    The UEVENT user mode helper is enabled before the initcalls are executed
    and is available when the root filesystem has been mounted.
    
    The user mode helper is triggered by device init calls and the executable
    might use the futex syscall.
    
    futex_init() is marked __initcall which maps to device_initcall, but there
    is no guarantee that futex_init() is invoked _before_ the first device init
    call which triggers the UEVENT user mode helper.
    
    If the user mode helper uses the futex syscall before futex_init() then the
    syscall crashes with a NULL pointer dereference because the futex subsystem
    has not been initialized yet.
    
    Move futex_init() to core_initcall so futexes are initialized before the
    root filesystem is mounted and the usermode helper becomes available.
    
    [ tglx: Rewrote changelog ]
    Signed-off-by: default avatarYang Yang <yang.yang29@zte.com.cn>
    Cc: jiang.biao2@zte.com.cn
    Cc: jiang.zhengxiong@zte.com.cn
    Cc: zhong.weidong@zte.com.cn
    Cc: deng.huali@zte.com.cn
    Cc: Peter Zijlstra <peterz@infradead.org>
    Link: http://lkml.kernel.org/r/1483085875-6130-1-git-send-email-yang.yang29@zte.com.cnSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
    dcc9b826
futex.c 81.7 KB