use schedule_timeout_uninterruptible() in nv_sleep_ms() #411
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nv_sleep_ms() function sets current process to TASK_INTERRUPTIBLE and call schedule_timeout() in a while loop until less than a jiffie remains. It retains in the loop regardless of whether signal is received. What's worse, process in TASK_INTERRUPTIBLE state with pending signal would be set back to TASK_RUNNING in __schedule() function, thus it would be rescheduled again and again, never get into sleep state. For example, processes calling nv_pci_remove() to remove a device which is still in use would stuck in the sleep-check loop until usage_count down do zero. Once SIGKILL received, it would remain in TASK_RUNNING, leading to a CPU usage at 100%. Instead, use schedule_timeout_uninterruptible() to substitute the while loop in nv_sleep_ms(). The process would not be woken up only when the requested timeout has expired. Signed-off-by: huteng.ht <[email protected]>
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nv_sleep_ms() function sets current process to TASK_INTERRUPTIBLE and call schedule_timeout() in a while loop until less than a jiffie remains. It retains in the loop regardless of whether signal is received. What's worse, process in TASK_INTERRUPTIBLE state with pending signal would be set back to TASK_RUNNING in __schedule() function, thus it would be rescheduled again and again, never get into sleep state.
For example, processes calling nv_pci_remove() to remove a device which is still in use would stuck in the sleep-check loop until usage_count down do zero. Once SIGKILL received, it would remain in TASK_RUNNING, leading to a CPU usage at 100%.
Instead, use schedule_timeout_uninterruptible() to substitute the while loop in nv_sleep_ms(). The process would not be woken up only when the requested timeout has expired.
Signed-off-by: huteng.ht [email protected]