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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-09-02 12:29:27 (GMT)
committerScott Wood <scottwood@freescale.com>2015-02-13 22:20:37 (GMT)
commit10f63fc1352dd1939b668f0210d02d27a90d298e (patch)
treebab115016e07278d62efecd277030c36b26477e8 /kernel
parent184f95de08a58adb4887ca6ff693b6f537976f54 (diff)
downloadlinux-fsl-qoriq-10f63fc1352dd1939b668f0210d02d27a90d298e.tar.xz
sched: teach migrate_disable about atomic contexts
<NMI> [<ffffffff812dafd8>] spin_bug+0x94/0xa8 [<ffffffff812db07f>] do_raw_spin_lock+0x43/0xea [<ffffffff814fa9be>] _raw_spin_lock_irqsave+0x6b/0x85 [<ffffffff8106ff9e>] ? migrate_disable+0x75/0x12d [<ffffffff81078aaf>] ? pin_current_cpu+0x36/0xb0 [<ffffffff8106ff9e>] migrate_disable+0x75/0x12d [<ffffffff81115b9d>] pagefault_disable+0xe/0x1f [<ffffffff81047027>] copy_from_user_nmi+0x74/0xe6 [<ffffffff810489d7>] perf_callchain_user+0xf3/0x135 Now clearly we can't go around taking locks from NMI context, cure this by short-circuiting migrate_disable() when we're in an atomic context already. Add some extra debugging to avoid things like: preempt_disable() migrate_disable(); preempt_enable(); migrate_enable(); Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1314967297.1301.14.camel@twins Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/n/tip-wbot4vsmwhi8vmbf83hsclk6@git.kernel.org
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/core.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index cb83fa1..13a5d9f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4423,6 +4423,17 @@ void migrate_disable(void)
unsigned long flags;
struct rq *rq;
+ if (in_atomic()) {
+#ifdef CONFIG_SCHED_DEBUG
+ p->migrate_disable_atomic++;
+#endif
+ return;
+ }
+
+#ifdef CONFIG_SCHED_DEBUG
+ WARN_ON_ONCE(p->migrate_disable_atomic);
+#endif
+
preempt_disable();
if (p->migrate_disable) {
p->migrate_disable++;
@@ -4471,6 +4482,16 @@ void migrate_enable(void)
unsigned long flags;
struct rq *rq;
+ if (in_atomic()) {
+#ifdef CONFIG_SCHED_DEBUG
+ p->migrate_disable_atomic--;
+#endif
+ return;
+ }
+
+#ifdef CONFIG_SCHED_DEBUG
+ WARN_ON_ONCE(p->migrate_disable_atomic);
+#endif
WARN_ON_ONCE(p->migrate_disable <= 0);
preempt_disable();