diff options
| author | Peter Zijlstra <[email protected]> | 2017-05-24 08:52:02 +0200 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2017-05-24 09:10:00 +0200 |
| commit | 45aea321678856687927c53972321ebfab77759a (patch) | |
| tree | 7e82415526d67107739c41076bc329e63d096c44 | |
| parent | 5c3c2ea6887176c5ae812c9f0350ff65b10e9485 (diff) | |
sched/clock: Fix early boot preempt assumption in __set_sched_clock_stable()
The more strict early boot preemption warnings found that
__set_sched_clock_stable() was incorrectly assuming we'd still be
running on a single CPU:
BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is debug_smp_processor_id+0x1c/0x1e
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0-rc2-00108-g1c3c5ea #1
Call Trace:
dump_stack+0x110/0x192
check_preemption_disabled+0x10c/0x128
? set_debug_rodata+0x25/0x25
debug_smp_processor_id+0x1c/0x1e
sched_clock_init_late+0x27/0x87
[...]
Fix it by disabling IRQs.
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
| -rw-r--r-- | kernel/sched/clock.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index 1a0d389d2f2b..ca0f8fc945c6 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -133,12 +133,19 @@ static void __scd_stamp(struct sched_clock_data *scd) static void __set_sched_clock_stable(void) { - struct sched_clock_data *scd = this_scd(); + struct sched_clock_data *scd; /* + * Since we're still unstable and the tick is already running, we have + * to disable IRQs in order to get a consistent scd->tick* reading. + */ + local_irq_disable(); + scd = this_scd(); + /* * Attempt to make the (initial) unstable->stable transition continuous. */ __sched_clock_offset = (scd->tick_gtod + __gtod_offset) - (scd->tick_raw); + local_irq_enable(); printk(KERN_INFO "sched_clock: Marking stable (%lld, %lld)->(%lld, %lld)\n", scd->tick_gtod, __gtod_offset, |