sched_ext: Fix scx_bpf_dsq_peek() with FIFO DSQs

Browse source

When removing a task from a FIFO DSQ, we must delete it from the list
before updating dsq->first_task, otherwise the following lookup will
just re-read the same task, leaving first_task pointing to removed
entry.

This issue only affects DSQs operating in FIFO mode, as priority DSQs
correctly update the rbtree before re-evaluating the new first task.

Remove the item from the list before refreshing the first task to
guarantee the correct behavior in FIFO DSQs.

Fixes: 44f5c8ec5b ("sched_ext: Add lockless peek operation for DSQs")
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

...

This commit is contained in:

Andrea Righi 2025-10-25 00:01:02 +02:00 • committed by Tejun Heo

parent e67708823d

commit 71d7847cad

1 changed files with 3 additions and 3 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

6

kernel/sched/ext.c

View file