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-rw-r--r--features/rt/kernel-sched-move-stack-kprobe-clean-up-to-__put_tas.patch80
1 files changed, 80 insertions, 0 deletions
diff --git a/features/rt/kernel-sched-move-stack-kprobe-clean-up-to-__put_tas.patch b/features/rt/kernel-sched-move-stack-kprobe-clean-up-to-__put_tas.patch
new file mode 100644
index 00000000..085edde5
--- /dev/null
+++ b/features/rt/kernel-sched-move-stack-kprobe-clean-up-to-__put_tas.patch
@@ -0,0 +1,80 @@
+From cb9ddd5eec36831a80572aa3d33be62eff791e74 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 21 Nov 2016 19:31:08 +0100
+Subject: [PATCH 121/191] kernel/sched: move stack + kprobe clean up to
+ __put_task_struct()
+
+There is no need to free the stack before the task struct (except for reasons
+mentioned in commit 68f24b08ee89 ("sched/core: Free the stack early if
+CONFIG_THREAD_INFO_IN_TASK")). This also comes handy on -RT because we can't
+free memory in preempt disabled region.
+vfree_atomic() delays the memory cleanup to a worker. Since we move everything
+to the RCU callback, we can also free it immediately.
+
+Cc: stable-rt@vger.kernel.org #for kprobe_flush_task()
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/fork.c | 12 +++++++++++-
+ kernel/sched/core.c | 9 ---------
+ 2 files changed, 11 insertions(+), 10 deletions(-)
+
+diff --git a/kernel/fork.c b/kernel/fork.c
+index da1b307cbf73..5fdb0a1bbad8 100644
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -42,6 +42,7 @@
+ #include <linux/mmu_notifier.h>
+ #include <linux/fs.h>
+ #include <linux/mm.h>
++#include <linux/kprobes.h>
+ #include <linux/vmacache.h>
+ #include <linux/nsproxy.h>
+ #include <linux/capability.h>
+@@ -288,7 +289,7 @@ static inline void free_thread_stack(struct task_struct *tsk)
+ return;
+ }
+
+- vfree_atomic(tsk->stack);
++ vfree(tsk->stack);
+ return;
+ }
+ #endif
+@@ -743,6 +744,15 @@ void __put_task_struct(struct task_struct *tsk)
+ WARN_ON(refcount_read(&tsk->usage));
+ WARN_ON(tsk == current);
+
++ /*
++ * Remove function-return probe instances associated with this
++ * task and put them back on the free list.
++ */
++ kprobe_flush_task(tsk);
++
++ /* Task is done with its stack. */
++ put_task_stack(tsk);
++
+ io_uring_free(tsk);
+ cgroup_free(tsk);
+ task_numa_free(tsk, true);
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 9ec24e4188f4..2069022bdce5 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -4282,15 +4282,6 @@ static struct rq *finish_task_switch(struct task_struct *prev)
+ if (prev->sched_class->task_dead)
+ prev->sched_class->task_dead(prev);
+
+- /*
+- * Remove function-return probe instances associated with this
+- * task and put them back on the free list.
+- */
+- kprobe_flush_task(prev);
+-
+- /* Task is done with its stack. */
+- put_task_stack(prev);
+-
+ put_task_struct_rcu_user(prev);
+ }
+
+--
+2.19.1
+