4.12-stable patches

added patches:
	sched-cputime-don-t-use-smp_processor_id-in-preemptible-context.patch

diff --git a/queue-4.12/sched-cputime-don-t-use-smp_processor_id-in-preemptible-context.patch b/queue-4.12/sched-cputime-don-t-use-smp_processor_id-in-preemptible-context.patch
new file mode 100644 (file)
index 0000000..1c53ab5
--- /dev/null
+++ b/queue-4.12/sched-cputime-don-t-use-smp_processor_id-in-preemptible-context.patch
@@ -0,0 +1,84 @@
+From 0e4097c3354e2f5a5ad8affd9dc7f7f7d00bb6b9 Mon Sep 17 00:00:00 2001
+From: Wanpeng Li <wanpeng.li@hotmail.com>
+Date: Sun, 9 Jul 2017 00:40:28 -0700
+Subject: sched/cputime: Don't use smp_processor_id() in preemptible context
+
+From: Wanpeng Li <wanpeng.li@hotmail.com>
+
+commit 0e4097c3354e2f5a5ad8affd9dc7f7f7d00bb6b9 upstream.
+
+Recent kernels trigger this warning:
+
+ BUG: using smp_processor_id() in preemptible [00000000] code: 99-trinity/181
+ caller is debug_smp_processor_id+0x17/0x19
+ CPU: 0 PID: 181 Comm: 99-trinity Not tainted 4.12.0-01059-g2a42eb9 #1
+ Call Trace:
+  dump_stack+0x82/0xb8
+  check_preemption_disabled()
+  debug_smp_processor_id()
+  vtime_delta()
+  task_cputime()
+  thread_group_cputime()
+  thread_group_cputime_adjusted()
+  wait_consider_task()
+  do_wait()
+  SYSC_wait4()
+  do_syscall_64()
+  entry_SYSCALL64_slow_path()
+
+As Frederic pointed out:
+
+| Although those sched_clock_cpu() things seem to only matter when the
+| sched_clock() is unstable. And that stability is a condition for nohz_full
+| to work anyway. So probably sched_clock() alone would be enough.
+
+This patch fixes it by replacing sched_clock_cpu() with sched_clock() to
+avoid calling smp_processor_id() in a preemptible context.
+
+Reported-by: Xiaolong Ye <xiaolong.ye@intel.com>
+Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
+Cc: Frederic Weisbecker <fweisbec@gmail.com>
+Cc: Linus Torvalds <torvalds@linux-foundation.org>
+Cc: Luiz Capitulino <lcapitulino@redhat.com>
+Cc: Peter Zijlstra <peterz@infradead.org>
+Cc: Rik van Riel <riel@redhat.com>
+Cc: Thomas Gleixner <tglx@linutronix.de>
+Link: http://lkml.kernel.org/r/1499586028-7402-1-git-send-email-wanpeng.li@hotmail.com
+[ Prettified the changelog. ]
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Signed-off-by: Mel Gorman <mgorman@suse.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ kernel/sched/cputime.c |    6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+--- a/kernel/sched/cputime.c
++++ b/kernel/sched/cputime.c
+@@ -683,7 +683,7 @@ static u64 vtime_delta(struct vtime *vti
+ {
+       unsigned long long clock;
+ 
+-      clock = sched_clock_cpu(smp_processor_id());
++      clock = sched_clock();
+       if (clock < vtime->starttime)
+               return 0;
+ 
+@@ -814,7 +814,7 @@ void arch_vtime_task_switch(struct task_
+ 
+       write_seqcount_begin(&vtime->seqcount);
+       vtime->state = VTIME_SYS;
+-      vtime->starttime = sched_clock_cpu(smp_processor_id());
++      vtime->starttime = sched_clock();
+       write_seqcount_end(&vtime->seqcount);
+ }
+ 
+@@ -826,7 +826,7 @@ void vtime_init_idle(struct task_struct
+       local_irq_save(flags);
+       write_seqcount_begin(&vtime->seqcount);
+       vtime->state = VTIME_SYS;
+-      vtime->starttime = sched_clock_cpu(cpu);
++      vtime->starttime = sched_clock();
+       write_seqcount_end(&vtime->seqcount);
+       local_irq_restore(flags);
+ }

diff --git a/queue-4.12/series b/queue-4.12/series
index f5e16996c2f89a5ef5d67b8fed014e7f7a1d5c7e..01fde0af9896f90ef1d55c8635ddf70e9f47f240 100644 (file)
--- a/queue-4.12/series
+++ b/queue-4.12/series
@@ -195,3 +195,4 @@ drm-i915-reintroduce-vlv-chv-pfi-programming-power-domain-workaround.patch
 smp-hotplug-move-unparking-of-percpu-threads-to-the-control-cpu.patch
 smp-hotplug-replace-bug_on-and-react-useful.patch
 alarmtimer-don-t-rate-limit-one-shot-timers.patch
+sched-cputime-don-t-use-smp_processor_id-in-preemptible-context.patch