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From 0d19bdfa59a3f9976aacac9944e5c2519f1a508b 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 216/323] kernel/sched: move stack + kprobe clean up to
__put_task_struct()
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
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 078058436f2f..2a11bf5f9e30 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
@@ -745,6 +746,15 @@ 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 5e5d28f5d970..81bc9efbd191 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4281,15 +4281,6 @@ 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);
}
--
2.43.0
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