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    Subject[PATCH][V3]Make get_user_pages interruptible
    From: Paul Menage <>

    make get_user_pages interruptible
    The initial implementation of checking TIF_MEMDIE covers the cases of OOM
    killing. If the process has been OOM killed, the TIF_MEMDIE is set and it
    return immediately. This patch includes:

    1. add the case that the SIGKILL is sent by user processes. The process can
    try to get_user_pages() unlimited memory even if a user process has sent a
    SIGKILL to it(maybe a monitor find the process exceed its memory limit and
    try to kill it). In the old implementation, the SIGKILL won't be handled
    until the get_user_pages() returns.

    2. change the return value to be ERESTARTSYS. It makes no sense to return
    ENOMEM if the get_user_pages returned by getting a SIGKILL signal.
    Considering the general convention for a system call interrupted by a
    signal is ERESTARTNOSYS, so the current return value is consistant to that.

    Signed-off-by: Paul Menage <>
    Singed-off-by: Ying Han <>

    include/linux/sched.h | 1 +
    kernel/signal.c | 2 +-
    mm/memory.c | 9 +-

    diff --git a/include/linux/sched.h b/include/linux/sched.h
    index b483f39..f9c6a8a 100644
    --- a/include/linux/sched.h
    +++ b/include/linux/sched.h
    @@ -1790,6 +1790,7 @@ extern void sched_dead(struct task_struct *p);
    extern int in_group_p(gid_t);
    extern int in_egroup_p(gid_t);

    +extern int sigkill_pending(struct task_struct *tsk);
    extern void proc_caches_init(void);
    extern void flush_signals(struct task_struct *);
    extern void ignore_signals(struct task_struct *);
    diff --git a/kernel/signal.c b/kernel/signal.c
    index 105217d..f3f154e 100644
    --- a/kernel/signal.c
    +++ b/kernel/signal.c
    @@ -1497,7 +1497,7 @@ static inline int may_ptrace_stop(void)
    * Return nonzero if there is a SIGKILL that should be waking us up.
    * Called with the siglock held.
    -static int sigkill_pending(struct task_struct *tsk)
    +int sigkill_pending(struct task_struct *tsk)
    return sigismember(&tsk->pending.signal, SIGKILL) ||
    sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
    diff --git a/mm/memory.c b/mm/memory.c
    index 164951c..ae24300 100644
    --- a/mm/memory.c
    +++ b/mm/memory.c
    @@ -1218,12 +1218,11 @@ int __get_user_pages(struct task_struct *tsk, struct m
    struct page *page;

    - * If tsk is ooming, cut off its access to large memory
    - * allocations. It has a pending SIGKILL, but it can't
    - * be processed until returning to user space.
    + * If we have a pending SIGKILL, don't keep
    + * allocating memory.
    - if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE)))
    - return i ? i : -ENOMEM;
    + if (unlikely(sigkill_pending(tsk)))
    + return i ? i : -ERESTARTSYS;

    if (write)
    foll_flags |= FOLL_WRITE;

     \ /
      Last update: 2008-11-22 02:35    [W:0.021 / U:2.784 seconds]
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