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| author | Peter Zijlstra <peterz@infradead.org> | 2022-09-27 21:02:34 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-09-28 10:00:16 +0200 |
| commit | 5aec788aeb8eb74282b75ac1b317beb0fbb69a42 (patch) | |
| tree | 0b191d9fffa590cbca17596e8c8c1147a42d14dc /kernel/hung_task.c | |
| parent | 7e9518baed4cef76dbfa07cbffbae1e6dbc87be6 (diff) | |
| download | linux-5aec788aeb8eb74282b75ac1b317beb0fbb69a42.tar.gz linux-5aec788aeb8eb74282b75ac1b317beb0fbb69a42.tar.bz2 linux-5aec788aeb8eb74282b75ac1b317beb0fbb69a42.zip | |
sched: Fix TASK_state comparisons
Task state is fundamentally a bitmask; direct comparisons are probably
not working as intended. Specifically the normal wait-state have
a number of possible modifiers:
TASK_UNINTERRUPTIBLE: TASK_WAKEKILL, TASK_NOLOAD, TASK_FREEZABLE
TASK_INTERRUPTIBLE: TASK_FREEZABLE
Specifically, the addition of TASK_FREEZABLE wrecked
__wait_is_interruptible(). This however led to an audit of direct
comparisons yielding the rest of the changes.
Fixes: f5d39b020809 ("freezer,sched: Rewrite core freezer logic")
Reported-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Debugged-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Diffstat (limited to 'kernel/hung_task.c')
| -rw-r--r-- | kernel/hung_task.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/hung_task.c b/kernel/hung_task.c index f1321c03c32a..3a15169ba2f8 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -191,6 +191,8 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) hung_task_show_lock = false; rcu_read_lock(); for_each_process_thread(g, t) { + unsigned int state; + if (!max_count--) goto unlock; if (time_after(jiffies, last_break + HUNG_TASK_LOCK_BREAK)) { @@ -198,8 +200,10 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) goto unlock; last_break = jiffies; } - /* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */ - if (READ_ONCE(t->__state) == TASK_UNINTERRUPTIBLE) + /* skip the TASK_KILLABLE tasks -- these can be killed */ + state = READ_ONCE(t->__state); + if ((state & TASK_UNINTERRUPTIBLE) && + !(state & TASK_WAKEKILL)) check_hung_task(t, timeout); } unlock: |