Merge tag 'timers-core-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip

Pull timer core updates from Thomas Gleixner:
 "Updates for the time/timer core subsystem:

   - Harden the user space controllable hrtimer interfaces further to
     protect against unpriviledged DoS attempts by arming timers in the
     past.

   - Add per-capacity hierarchies to the timer migration code to prevent
     timer migration accross different capacity domains. This code has
     been disabled last minute as there is a pathological problem with
     SoCs which advertise a larger number of capacity domains. The
     problem is under investigation and the code won't be active before
     v7.3, but that turned out to be less intrusive than a full revert
     as it preserves the preparatory steps and allows people to work on
     the final resolution

   - Export time namespace functionality as a recent user can be built
     as a module.

   - Initialize the jiffies clocksource before using it. The recent
     hardening against time moving backward requires that the related
     members of struct clocksource have been initialized, otherwise it
     clamps the readout to 0, which makes time stand sill and causes
     boot delays.

   - Fix a more than twenty year old PID reference count leak in an
     error path of the POSIX CPU timer code.

   - The usual small fixes, improvements and cleanups all over the
     place"

* tag 'timers-core-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (31 commits)
  posix-cpu-timers: Fix pid refcount leak in do_cpu_nanosleep() error path
  time/jiffies: Register jiffies clocksource before usage
  timers/migration: Temporarily disable per capacity hierarchies
  timers/migration: Turn tmigr_hierarchy level_list into a flexible array
  timers/migration: Deactivate per-capacity hierarchies under nohz_full
  timers/migration: Fix hotplug migrator selection target on asymetric capacity machines
  ntsync: Honour caller's time namespace for absolute MONOTONIC timeouts
  time/namespace: Export init_time_ns and do_timens_ktime_to_host()
  timers/migration: Update stale @online doc to @available
  timers: Fix flseep() typo in kernel-doc comment
  hrtimer: Fix the bogus return type of __hrtimer_start_range_ns()
  hrtimer: Return ktime_t from hrtimer_get_next_event()/hrtimer_next_event_without()
  clocksource: Clean up clocksource_update_freq() functions
  alarmtimer: Remove stale return description from alarm_handle_timer()
  selftests/posix_timers: Use CLOCK_THREAD_CPUTIME_ID for ITIMER_PROF measurements
  scripts/timers: Add timer_migration_tree.py
  timers/migration: Handle capacity in connect tracepoints
  timers/migration: Split per-capacity hierarchies
  timers/migration: Track CPUs in a hierarchy
  timers/migration: Abstract out hierarchy to prepare for CPU capacity awareness
  ...

1 files changed, 28 insertions, 27 deletions

diff --git a/tools/testing/selftests/timers/posix_timers.c b/tools/testing/selftests/timers/posix_timers.c
index 38512623622a..2f3bac9fc6e8 100644
--- a/tools/testing/selftests/timers/posix_timers.c
+++ b/tools/testing/selftests/timers/posix_timers.c
@@ -78,19 +78,25 @@ static void sig_handler(int nr)
 	done = 1;
 }
 
+static inline int64_t calcdiff_ns(struct timespec t1, struct timespec t2)
+{
+	int64_t diff;
+
+	diff = NSEC_PER_SEC * (int64_t)((int) t1.tv_sec - (int) t2.tv_sec);
+	diff += ((int) t1.tv_nsec - (int) t2.tv_nsec);
+	return diff;
+}
+
 /*
  * Check the expected timer expiration matches the GTOD elapsed delta since
  * we armed the timer. Keep a 0.5 sec error margin due to various jitter.
  */
-static int check_diff(struct timeval start, struct timeval end)
+static int check_diff(struct timespec start, struct timespec end)
 {
-	long long diff;
-
-	diff = end.tv_usec - start.tv_usec;
-	diff += (end.tv_sec - start.tv_sec) * USEC_PER_SEC;
+	long long diff = calcdiff_ns(end, start);
 
-	if (llabs(diff - DELAY * USEC_PER_SEC) > USEC_PER_SEC / 2) {
-		printf("Diff too high: %lld..", diff);
+	if (llabs(diff - DELAY * NSEC_PER_SEC) > NSEC_PER_SEC / 2) {
+		printf("Diff too high: %lld ns..", diff);
 		return -1;
 	}
 
@@ -99,22 +105,25 @@ static int check_diff(struct timeval start, struct timeval end)
 
 static void check_itimer(int which, const char *name)
 {
-	struct timeval start, end;
+	struct timespec start, end;
 	struct itimerval val = {
 		.it_value.tv_sec = DELAY,
 	};
+	int clock_id = CLOCK_REALTIME;
 
 	done = 0;
 
 	if (which == ITIMER_VIRTUAL)
 		signal(SIGVTALRM, sig_handler);
-	else if (which == ITIMER_PROF)
+	else if (which == ITIMER_PROF) {
+		clock_id = CLOCK_THREAD_CPUTIME_ID;
 		signal(SIGPROF, sig_handler);
+	}
 	else if (which == ITIMER_REAL)
 		signal(SIGALRM, sig_handler);
 
-	if (gettimeofday(&start, NULL) < 0)
-		fatal_error(name, "gettimeofday()");
+	if (clock_gettime(clock_id, &start))
+		fatal_error(name, "clock_gettime()");
 
 	if (setitimer(which, &val, NULL) < 0)
 		fatal_error(name, "setitimer()");
@@ -126,18 +135,19 @@ static void check_itimer(int which, const char *name)
 	else if (which == ITIMER_REAL)
 		idle_loop();
 
-	if (gettimeofday(&end, NULL) < 0)
-		fatal_error(name, "gettimeofday()");
+	if (clock_gettime(clock_id, &end))
+		fatal_error(name, "clock_gettime()");
 
 	ksft_test_result(check_diff(start, end) == 0, "%s\n", name);
 }
 
 static void check_timer_create(int which, const char *name)
 {
-	struct timeval start, end;
+	struct timespec start, end;
 	struct itimerspec val = {
 		.it_value.tv_sec = DELAY,
 	};
+	int clock_id = CLOCK_REALTIME;
 	timer_t id;
 
 	done = 0;
@@ -148,16 +158,16 @@ static void check_timer_create(int which, const char *name)
 	if (signal(SIGALRM, sig_handler) == SIG_ERR)
 		fatal_error(name, "signal()");
 
-	if (gettimeofday(&start, NULL) < 0)
-		fatal_error(name, "gettimeofday()");
+	if (clock_gettime(clock_id, &start))
+		fatal_error(name, "clock_gettime()");
 
 	if (timer_settime(id, 0, &val, NULL) < 0)
 		fatal_error(name, "timer_settime()");
 
 	user_loop();
 
-	if (gettimeofday(&end, NULL) < 0)
-		fatal_error(name, "gettimeofday()");
+	if (clock_gettime(clock_id, &end))
+		fatal_error(name, "clock_gettime()");
 
 	ksft_test_result(check_diff(start, end) == 0,
 			 "timer_create() per %s\n", name);
@@ -445,15 +455,6 @@ static void check_delete(void)
 	ksft_test_result(!tsig.signals, "check_delete\n");
 }
 
-static inline int64_t calcdiff_ns(struct timespec t1, struct timespec t2)
-{
-	int64_t diff;
-
-	diff = NSEC_PER_SEC * (int64_t)((int) t1.tv_sec - (int) t2.tv_sec);
-	diff += ((int) t1.tv_nsec - (int) t2.tv_nsec);
-	return diff;
-}
-
 static void check_sigev_none(int which, const char *name)
 {
 	struct timespec start, now;