diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2025-02-08 11:55:03 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-02-08 11:55:03 -0800 |
| commit | 3a0562d733b19d5f10ebf7643dab0ab1a4fd8cf7 (patch) | |
| tree | 2a526e9d3737808adce0600a66d2d42b4e4202b8 /kernel | |
| parent | c7b92e8969cd60a585629cef8d19b7ef330bc171 (diff) | |
| parent | 868c9037df626b3c245ee26a290a03ae1f9f58d3 (diff) | |
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
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/clocksource.c | 6 | ||||
| -rw-r--r-- | kernel/time/timer_migration.c | 10 |
2 files changed, 13 insertions, 3 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 77d9566d3aa6..2a7802ec480c 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -373,10 +373,10 @@ void clocksource_verify_percpu(struct clocksource *cs) cpumask_clear(&cpus_ahead); cpumask_clear(&cpus_behind); cpus_read_lock(); - preempt_disable(); + migrate_disable(); clocksource_verify_choose_cpus(); if (cpumask_empty(&cpus_chosen)) { - preempt_enable(); + migrate_enable(); cpus_read_unlock(); pr_warn("Not enough CPUs to check clocksource '%s'.\n", cs->name); return; @@ -384,6 +384,7 @@ void clocksource_verify_percpu(struct clocksource *cs) testcpu = smp_processor_id(); pr_info("Checking clocksource %s synchronization from CPU %d to CPUs %*pbl.\n", cs->name, testcpu, cpumask_pr_args(&cpus_chosen)); + preempt_disable(); for_each_cpu(cpu, &cpus_chosen) { if (cpu == testcpu) continue; @@ -403,6 +404,7 @@ void clocksource_verify_percpu(struct clocksource *cs) cs_nsec_min = cs_nsec; } preempt_enable(); + migrate_enable(); cpus_read_unlock(); if (!cpumask_empty(&cpus_ahead)) pr_warn(" CPUs %*pbl ahead of CPU %d for clocksource %s.\n", diff --git a/kernel/time/timer_migration.c b/kernel/time/timer_migration.c index 9cb9b6584ea1..2f6330831f08 100644 --- a/kernel/time/timer_migration.c +++ b/kernel/time/timer_migration.c @@ -1675,6 +1675,9 @@ static int tmigr_setup_groups(unsigned int cpu, unsigned int node) } while (i < tmigr_hierarchy_levels); + /* Assert single root */ + WARN_ON_ONCE(!err && !group->parent && !list_is_singular(&tmigr_level_list[top])); + while (i > 0) { group = stack[--i]; @@ -1716,7 +1719,12 @@ static int tmigr_setup_groups(unsigned int cpu, unsigned int node) WARN_ON_ONCE(top == 0); lvllist = &tmigr_level_list[top]; - if (group->num_children == 1 && list_is_singular(lvllist)) { + + /* + * Newly created root level should have accounted the upcoming + * CPU's child group and pre-accounted the old root. + */ + if (group->num_children == 2 && list_is_singular(lvllist)) { /* * The target CPU must never do the prepare work, except * on early boot when the boot CPU is the target. Otherwise |