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    kmod: make __request_module() killable · 1cc684ab
    Oleg Nesterov 提交于
    As Tetsuo Handa pointed out, request_module() can stress the system
    while the oom-killed caller sleeps in TASK_UNINTERRUPTIBLE.
    
    The task T uses "almost all" memory, then it does something which
    triggers request_module().  Say, it can simply call sys_socket().  This
    in turn needs more memory and leads to OOM.  oom-killer correctly
    chooses T and kills it, but this can't help because it sleeps in
    TASK_UNINTERRUPTIBLE and after that oom-killer becomes "disabled" by the
    TIF_MEMDIE task T.
    
    Make __request_module() killable.  The only necessary change is that
    call_modprobe() should kmalloc argv and module_name, they can't live in
    the stack if we use UMH_KILLABLE.  This memory is freed via
    call_usermodehelper_freeinfo()->cleanup.
    Reported-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
    Signed-off-by: NOleg Nesterov <oleg@redhat.com>
    Cc: Rusty Russell <rusty@rustcorp.com.au>
    Cc: Tejun Heo <tj@kernel.org>
    Cc: David Rientjes <rientjes@google.com>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    1cc684ab
kmod.c 16.0 KB