sched/core: Report correct state for TASK_IDLE | TASK_FREEZABLE

[ Upstream commit 0d6b35283bcf1a379cf20066544af8e6a6b16b46 ]

task_state_index() ignores uninteresting state flags (such as
TASK_FREEZABLE) for most states, but for TASK_IDLE and TASK_RTLOCK_WAIT
it does not.

So if a task is waiting TASK_IDLE|TASK_FREEZABLE it gets incorrectly
reported as TASK_UNINTERRUPTIBLE or "D".  (it is planned for nfsd to
change to use this state).

Fix this by only testing the interesting bits and not the irrelevant
bits in __task_state_index()

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/169335025927.5133.4781141800413736103@noble.neil.brown.name
Stable-dep-of: f718faf3940e ("freezer, sched: Report frozen tasks as 'D' instead of 'R'")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0cac69902ec5806ff7765fa80199bde668c8d35a..205a008068352b380c19489506820737a392a47d 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1663,7 +1663,7 @@ static inline unsigned int __task_state_index(unsigned int tsk_state,
 
        BUILD_BUG_ON_NOT_POWER_OF_2(TASK_REPORT_MAX);
 
-       if (tsk_state == TASK_IDLE)
+       if ((tsk_state & TASK_IDLE) == TASK_IDLE)
                state = TASK_REPORT_IDLE;
 
        /*
@@ -1671,7 +1671,7 @@ static inline unsigned int __task_state_index(unsigned int tsk_state,
         * to userspace, we can make this appear as if the task has gone through
         * a regular rt_mutex_lock() call.
         */
-       if (tsk_state == TASK_RTLOCK_WAIT)
+       if (tsk_state & TASK_RTLOCK_WAIT)
                state = TASK_UNINTERRUPTIBLE;
 
        return fls(state);