2021-12-08 15:15:15

by Jerome Marchand

Subject: [PATCH] ftrace: disable preemption when recursion locked in arch/s390/kernel/ftrace.c

It looks like commit ce5e48036c9e76a2 ("ftrace: disable preemption
when recursion locked") missed a spot in kprobe_ftrace_handler() in
arch/s390/kernel/ftrace.c.
Removes the superfluous preempt_disable/enable_notrace() there too.

Fixes: ce5e48036c9e76a2 ("ftrace: disable preemption when recursion locked")
Signed-off-by: Jerome Marchand <[email protected]>
---
arch/s390/kernel/ftrace.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 5510c7d10ddc..21d62d8b6b9a 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -290,7 +290,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
return;

regs = ftrace_get_regs(fregs);
- preempt_disable_notrace();
p = get_kprobe((kprobe_opcode_t *)ip);
if (unlikely(!p) || kprobe_disabled(p))
goto out;
@@ -318,7 +317,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
}
__this_cpu_write(current_kprobe, NULL);
out:
- preempt_enable_notrace();
ftrace_test_recursion_unlock(bit);
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
--
2.31.1

2021-12-08 15:20:19

by Steven Rostedt

Subject: Re: [PATCH] ftrace: disable preemption when recursion locked in arch/s390/kernel/ftrace.c

This really needs to go through the s390 tree.

-- Steve


On Wed, 8 Dec 2021 16:15:03 +0100
"Jerome Marchand" <[email protected]> wrote:

> It looks like commit ce5e48036c9e76a2 ("ftrace: disable preemption
> when recursion locked") missed a spot in kprobe_ftrace_handler() in
> arch/s390/kernel/ftrace.c.
> Removes the superfluous preempt_disable/enable_notrace() there too.
>
> Fixes: ce5e48036c9e76a2 ("ftrace: disable preemption when recursion locked")
> Signed-off-by: Jerome Marchand <[email protected]>
> ---
> arch/s390/kernel/ftrace.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
> index 5510c7d10ddc..21d62d8b6b9a 100644
> --- a/arch/s390/kernel/ftrace.c
> +++ b/arch/s390/kernel/ftrace.c
> @@ -290,7 +290,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
> return;
>
> regs = ftrace_get_regs(fregs);
> - preempt_disable_notrace();
> p = get_kprobe((kprobe_opcode_t *)ip);
> if (unlikely(!p) || kprobe_disabled(p))
> goto out;
> @@ -318,7 +317,6 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
> }
> __this_cpu_write(current_kprobe, NULL);
> out:
> - preempt_enable_notrace();
> ftrace_test_recursion_unlock(bit);
> }
> NOKPROBE_SYMBOL(kprobe_ftrace_handler);

2021-12-08 15:48:32

by Heiko Carstens

Subject: Re: [PATCH] ftrace: disable preemption when recursion locked in arch/s390/kernel/ftrace.c

On Wed, Dec 08, 2021 at 04:15:03PM +0100, Jerome Marchand wrote:
> It looks like commit ce5e48036c9e76a2 ("ftrace: disable preemption
> when recursion locked") missed a spot in kprobe_ftrace_handler() in
> arch/s390/kernel/ftrace.c.
> Removes the superfluous preempt_disable/enable_notrace() there too.
>
> Fixes: ce5e48036c9e76a2 ("ftrace: disable preemption when recursion locked")
> Signed-off-by: Jerome Marchand <[email protected]>
> ---
> arch/s390/kernel/ftrace.c | 2 --
> 1 file changed, 2 deletions(-)

Applied to s390 tree. Thanks!