This is a note to let you know that I've just added the patch titled
s390/runtime instrumentation: simplify task exit handling
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
s390-runtime-instrumentation-simplify-task-exit-handling.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8d9047f8b967ce6181fd824ae922978e1b055cc0 Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Date: Mon, 11 Sep 2017 11:24:22 +0200
Subject: s390/runtime instrumentation: simplify task exit handling
From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
commit 8d9047f8b967ce6181fd824ae922978e1b055cc0 upstream.
Free data structures required for runtime instrumentation from
arch_release_task_struct(). This allows to simplify the code a bit,
and also makes the semantics a bit easier: arch_release_task_struct()
is never called from the task that is being removed.
In addition this allows to get rid of exit_thread() in a later patch.
Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/include/asm/runtime_instr.h | 4 +++-
arch/s390/kernel/process.c | 2 +-
arch/s390/kernel/runtime_instr.c | 30 +++++++++++++++---------------
3 files changed, 19 insertions(+), 17 deletions(-)
--- a/arch/s390/include/asm/runtime_instr.h
+++ b/arch/s390/include/asm/runtime_instr.h
@@ -85,6 +85,8 @@ static inline void restore_ri_cb(struct
load_runtime_instr_cb(&runtime_instr_empty_cb);
}
-void exit_thread_runtime_instr(void);
+struct task_struct;
+
+void runtime_instr_release(struct task_struct *tsk);
#endif /* _RUNTIME_INSTR_H */
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -72,7 +72,6 @@ extern void kernel_thread_starter(void);
*/
void exit_thread(void)
{
- exit_thread_runtime_instr();
}
void flush_thread(void)
@@ -87,6 +86,7 @@ void arch_release_task_struct(struct tas
{
/* Free either the floating-point or the vector register save area */
kfree(tsk->thread.fpu.regs);
+ runtime_instr_release(tsk);
}
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
--- a/arch/s390/kernel/runtime_instr.c
+++ b/arch/s390/kernel/runtime_instr.c
@@ -18,11 +18,24 @@
/* empty control block to disable RI by loading it */
struct runtime_instr_cb runtime_instr_empty_cb;
+void runtime_instr_release(struct task_struct *tsk)
+{
+ kfree(tsk->thread.ri_cb);
+}
+
static void disable_runtime_instr(void)
{
- struct pt_regs *regs = task_pt_regs(current);
+ struct task_struct *task = current;
+ struct pt_regs *regs;
+ if (!task->thread.ri_cb)
+ return;
+ regs = task_pt_regs(task);
+ preempt_disable();
load_runtime_instr_cb(&runtime_instr_empty_cb);
+ kfree(task->thread.ri_cb);
+ task->thread.ri_cb = NULL;
+ preempt_enable();
/*
* Make sure the RI bit is deleted from the PSW. If the user did not
@@ -43,19 +56,6 @@ static void init_runtime_instr_cb(struct
cb->valid = 1;
}
-void exit_thread_runtime_instr(void)
-{
- struct task_struct *task = current;
-
- preempt_disable();
- if (!task->thread.ri_cb)
- return;
- disable_runtime_instr();
- kfree(task->thread.ri_cb);
- task->thread.ri_cb = NULL;
- preempt_enable();
-}
-
SYSCALL_DEFINE1(s390_runtime_instr, int, command)
{
struct runtime_instr_cb *cb;
@@ -64,7 +64,7 @@ SYSCALL_DEFINE1(s390_runtime_instr, int,
return -EOPNOTSUPP;
if (command == S390_RUNTIME_INSTR_STOP) {
- exit_thread_runtime_instr();
+ disable_runtime_instr();
return 0;
}
Patches currently in stable-queue which might be from heiko.carstens@xxxxxxxxxx are
queue-4.4/s390-runtime-instrumentation-simplify-task-exit-handling.patch