From: Wander Lairson Costa wander@redhat.com

[ Upstream commit 0664e2c311b9fa43b33e3e81429cd0c2d7f9c638 ]

When running the following command:

while true; do stress-ng --cyclic 30 --timeout 30s --minimize --quiet done

a warning is eventually triggered:

WARNING: CPU: 43 PID: 2848 at kernel/sched/deadline.c:794 setup_new_dl_entity+0x13e/0x180 ... Call Trace: <TASK> ? show_trace_log_lvl+0x1c4/0x2df ? enqueue_dl_entity+0x631/0x6e0 ? setup_new_dl_entity+0x13e/0x180 ? __warn+0x7e/0xd0 ? report_bug+0x11a/0x1a0 ? handle_bug+0x3c/0x70 ? exc_invalid_op+0x14/0x70 ? asm_exc_invalid_op+0x16/0x20 enqueue_dl_entity+0x631/0x6e0 enqueue_task_dl+0x7d/0x120 __do_set_cpus_allowed+0xe3/0x280 __set_cpus_allowed_ptr_locked+0x140/0x1d0 __set_cpus_allowed_ptr+0x54/0xa0 migrate_enable+0x7e/0x150 rt_spin_unlock+0x1c/0x90 group_send_sig_info+0xf7/0x1a0 ? kill_pid_info+0x1f/0x1d0 kill_pid_info+0x78/0x1d0 kill_proc_info+0x5b/0x110 __x64_sys_kill+0x93/0xc0 do_syscall_64+0x5c/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 RIP: 0033:0x7f0dab31f92b

This warning occurs because set_cpus_allowed dequeues and enqueues tasks with the ENQUEUE_RESTORE flag set. If the task is boosted, the warning is triggered. A boosted task already had its parameters set by rt_mutex_setprio, and a new call to setup_new_dl_entity is unnecessary, hence the WARN_ON call.

Check if we are requeueing a boosted task and avoid calling setup_new_dl_entity if that's the case.

Fixes: 295d6d5e3736 ("sched/deadline: Fix switching to -deadline") Signed-off-by: Wander Lairson Costa wander@redhat.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Acked-by: Juri Lelli juri.lelli@redhat.com Link: https://lore.kernel.org/r/20240724142253.27145-2-wander@redhat.com [Minor context change fixed.] Signed-off-by: Bin Lan bin.lan.cn@windriver.com Signed-off-by: He Zhe zhe.he@windriver.com --- Build test passed. --- kernel/sched/deadline.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 6548bd90c5c3..e2ff343d1c42 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1516,6 +1516,7 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se, int flags) } else if (flags & ENQUEUE_REPLENISH) { replenish_dl_entity(dl_se); } else if ((flags & ENQUEUE_RESTORE) && + !is_dl_boosted(dl_se) && dl_time_before(dl_se->deadline, rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) { setup_new_dl_entity(dl_se);