Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'timers-urgent-2025-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Ingo Molnar:
"Fix a PREEMPT_RT bug in the clocksource verification code that caused
false positive warnings.
Also fix a timer migration setup bug when new CPUs are added"
* tag 'timers-urgent-2025-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timers/migration: Fix off-by-one root mis-connection
clocksource: Use migrate_disable() to avoid calling get_random_u32() in atomic context
+13
-3
+4
-2
kernel/time/clocksource.c
+4
-2
kernel/time/clocksource.c
···
373
373
cpumask_clear(&cpus_ahead);
374
374
cpumask_clear(&cpus_behind);
375
375
cpus_read_lock();
376
-
preempt_disable();
376
+
migrate_disable();
377
377
clocksource_verify_choose_cpus();
378
378
if (cpumask_empty(&cpus_chosen)) {
379
-
preempt_enable();
379
+
migrate_enable();
380
380
cpus_read_unlock();
381
381
pr_warn("Not enough CPUs to check clocksource '%s'.\n", cs->name);
382
382
return;
···
384
384
testcpu = smp_processor_id();
385
385
pr_info("Checking clocksource %s synchronization from CPU %d to CPUs %*pbl.\n",
386
386
cs->name, testcpu, cpumask_pr_args(&cpus_chosen));
387
+
preempt_disable();
387
388
for_each_cpu(cpu, &cpus_chosen) {
388
389
if (cpu == testcpu)
389
390
continue;
···
404
403
cs_nsec_min = cs_nsec;
405
404
}
406
405
preempt_enable();
406
+
migrate_enable();
407
407
cpus_read_unlock();
408
408
if (!cpumask_empty(&cpus_ahead))
409
409
pr_warn(" CPUs %*pbl ahead of CPU %d for clocksource %s.\n",
+9
-1
kernel/time/timer_migration.c
+9
-1
kernel/time/timer_migration.c
···
1675
1675
1676
1676
} while (i < tmigr_hierarchy_levels);
1677
1677
1678
+
/* Assert single root */
1679
+
WARN_ON_ONCE(!err && !group->parent && !list_is_singular(&tmigr_level_list[top]));
1680
+
1678
1681
while (i > 0) {
1679
1682
group = stack[--i];
1680
1683
···
1719
1716
WARN_ON_ONCE(top == 0);
1720
1717
1721
1718
lvllist = &tmigr_level_list[top];
1722
-
if (group->num_children == 1 && list_is_singular(lvllist)) {
1719
+
1720
+
/*
1721
+
* Newly created root level should have accounted the upcoming
1722
+
* CPU's child group and pre-accounted the old root.
1723
+
*/
1724
+
if (group->num_children == 2 && list_is_singular(lvllist)) {
1723
1725
/*
1724
1726
* The target CPU must never do the prepare work, except
1725
1727
* on early boot when the boot CPU is the target. Otherwise