- Prevent PSI state corruption when schedule() races with cgroup move. A
recent commit combined two PSI callbacks to reduce the number of cgroup
tree updates, but missed that schedule() can drop rq::lock for load
balancing, which opens the race window for cgroup_move_task() which then
observes half updated state. The fix is to solely use task::ps_flags
instead of looking at the potentially mismatching scheduler state
- Prevent an out-of-bounds access in uclamp caused bu a rounding division
which can lead to an off-by-one error exceeding the buckets array size.
- Prevent unfairness caused by missing load decay when a task is attached
to a cfs runqueue. The old load of the task is attached to the runqueue
and never removed. Fix it by enforcing the load update through the
hierarchy for unthrottled run queue instances.
- A documentation fix fot the 'sched_verbose' command line option
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Merge tag 'sched-urgent-2021-05-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Thomas Gleixner:
"A set of scheduler updates:
- Prevent PSI state corruption when schedule() races with cgroup
move.
A recent commit combined two PSI callbacks to reduce the number of
cgroup tree updates, but missed that schedule() can drop rq::lock
for load balancing, which opens the race window for
cgroup_move_task() which then observes half updated state.
The fix is to solely use task::ps_flags instead of looking at the
potentially mismatching scheduler state
- Prevent an out-of-bounds access in uclamp caused bu a rounding
division which can lead to an off-by-one error exceeding the
buckets array size.
- Prevent unfairness caused by missing load decay when a task is
attached to a cfs runqueue.
The old load of the task was attached to the runqueue and never
removed. Fix it by enforcing the load update through the hierarchy
for unthrottled run queue instances.
- A documentation fix fot the 'sched_verbose' command line option"
* tag 'sched-urgent-2021-05-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Fix unfairness caused by missing load decay
sched: Fix out-of-bound access in uclamp
psi: Fix psi state corruption when schedule() races with cgroup move
sched,doc: sched_debug_verbose cmdline should be sched_verbose
9819f682e4