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authorThomas Gleixner <tglx@linutronix.de>2021-09-28 14:24:28 +0200
committerPeter Zijlstra <peterz@infradead.org>2021-10-05 15:52:14 +0200
commit670721c7bd2a6e16e40db29b2707a27bdecd6928 (patch)
tree27ead0ffba4532ed1e500925b7d9b1783bd6687f /kernel
parentsched: Disable TTWU_QUEUE on RT (diff)
downloadlinux-670721c7bd2a6e16e40db29b2707a27bdecd6928.tar.xz
linux-670721c7bd2a6e16e40db29b2707a27bdecd6928.zip
sched: Move kprobes cleanup out of finish_task_switch()
Doing cleanups in the tail of schedule() is a latency punishment for the incoming task. The point of invoking kprobes_task_flush() for a dead task is that the instances are returned and cannot leak when __schedule() is kprobed. Move it into the delayed cleanup. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210928122411.537994026@linutronix.de
Diffstat (limited to 'kernel')
-rw-r--r--kernel/exit.c2
-rw-r--r--kernel/kprobes.c8
-rw-r--r--kernel/sched/core.c6
3 files changed, 6 insertions, 10 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 91a43e57a32e..63851320ae73 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -64,6 +64,7 @@
#include <linux/rcuwait.h>
#include <linux/compat.h>
#include <linux/io_uring.h>
+#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
@@ -168,6 +169,7 @@ static void delayed_put_task_struct(struct rcu_head *rhp)
{
struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
+ kprobe_flush_task(tsk);
perf_event_delayed_put(tsk);
trace_sched_process_free(tsk);
put_task_struct(tsk);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 790a573bbe00..9a38e7581a5c 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1250,10 +1250,10 @@ void kprobe_busy_end(void)
}
/*
- * This function is called from finish_task_switch when task tk becomes dead,
- * so that we can recycle any function-return probe instances associated
- * with this task. These left over instances represent probed functions
- * that have been called but will never return.
+ * This function is called from delayed_put_task_struct() when a task is
+ * dead and cleaned up to recycle any function-return probe instances
+ * associated with this task. These left over instances represent probed
+ * functions that have been called but will never return.
*/
void kprobe_flush_task(struct task_struct *tk)
{
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 749284fc3c1f..e33b03c2bb9a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4846,12 +4846,6 @@ 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);