diff options
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 47 |
1 files changed, 27 insertions, 20 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 733e80f334e7..3594291a8542 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -454,7 +454,10 @@ static void exit_mm(void) mmap_read_unlock(mm); self.task = current; - self.next = xchg(&core_state->dumper.next, &self); + if (self.task->flags & PF_SIGNALED) + self.next = xchg(&core_state->dumper.next, &self); + else + self.task = NULL; /* * Implies mb(), the result of xchg() must be visible * to core_state->dumper. @@ -475,10 +478,24 @@ static void exit_mm(void) BUG_ON(mm != current->active_mm); /* more a memory barrier than a real lock */ task_lock(current); + /* + * When a thread stops operating on an address space, the loop + * in membarrier_private_expedited() may not observe that + * tsk->mm, and the loop in membarrier_global_expedited() may + * not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED + * rq->membarrier_state, so those would not issue an IPI. + * Membarrier requires a memory barrier after accessing + * user-space memory, before clearing tsk->mm or the + * rq->membarrier_state. + */ + smp_mb__after_spinlock(); + local_irq_disable(); current->mm = NULL; - mmap_read_unlock(mm); + membarrier_update_current_mm(NULL); enter_lazy_tlb(mm, current); + local_irq_enable(); task_unlock(current); + mmap_read_unlock(mm); mm_update_next_owner(mm); mmput(mm); if (test_thread_flag(TIF_MEMDIE)) @@ -1474,23 +1491,6 @@ end: return retval; } -static struct pid *pidfd_get_pid(unsigned int fd) -{ - struct fd f; - struct pid *pid; - - f = fdget(fd); - if (!f.file) - return ERR_PTR(-EBADF); - - pid = pidfd_pid(f.file); - if (!IS_ERR(pid)) - get_pid(pid); - - fdput(f); - return pid; -} - static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop, int options, struct rusage *ru) { @@ -1498,6 +1498,7 @@ static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop, struct pid *pid = NULL; enum pid_type type; long ret; + unsigned int f_flags = 0; if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED| __WNOTHREAD|__WCLONE|__WALL)) @@ -1531,9 +1532,10 @@ static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop, if (upid < 0) return -EINVAL; - pid = pidfd_get_pid(upid); + pid = pidfd_get_pid(upid, &f_flags); if (IS_ERR(pid)) return PTR_ERR(pid); + break; default: return -EINVAL; @@ -1544,7 +1546,12 @@ static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop, wo.wo_flags = options; wo.wo_info = infop; wo.wo_rusage = ru; + if (f_flags & O_NONBLOCK) + wo.wo_flags |= WNOHANG; + ret = do_wait(&wo); + if (!ret && !(options & WNOHANG) && (f_flags & O_NONBLOCK)) + ret = -EAGAIN; put_pid(pid); return ret; |