2021-01-13 13:48:34

by Marcus Huewe

Subject: [PATCH] ptrace: Remove redundant code in ptrace_attach

In case of a PTRACE_SEIZE request, the PT_SEIZED flag is always set
at the beginning of ptrace_attach. Hence, there is no need to set
it again (neither "flags" nor "seize" are modified in between/after
the initial assignment).

Signed-off-by: Marcus Huewe <[email protected]>
---
kernel/ptrace.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 61db50f7ca86..059fce2ad53c 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -402,8 +402,6 @@ static int ptrace_attach(struct task_struct *task, long request,
if (task->ptrace)
goto unlock_tasklist;

- if (seize)
- flags |= PT_SEIZED;
task->ptrace = flags;

ptrace_link(task, current);
--
2.29.2

2021-01-13 15:37:04

by Oleg Nesterov

Subject: Re: [PATCH] ptrace: Remove redundant code in ptrace_attach

Acked-by: Oleg Nesterov <[email protected]>


On 01/13, Marcus Huewe wrote:
>
> In case of a PTRACE_SEIZE request, the PT_SEIZED flag is always set
> at the beginning of ptrace_attach. Hence, there is no need to set
> it again (neither "flags" nor "seize" are modified in between/after
> the initial assignment).
>
> Signed-off-by: Marcus Huewe <[email protected]>
> ---
> kernel/ptrace.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/kernel/ptrace.c b/kernel/ptrace.c
> index 61db50f7ca86..059fce2ad53c 100644
> --- a/kernel/ptrace.c
> +++ b/kernel/ptrace.c
> @@ -402,8 +402,6 @@ static int ptrace_attach(struct task_struct *task, long request,
> if (task->ptrace)
> goto unlock_tasklist;
>
> - if (seize)
> - flags |= PT_SEIZED;
> task->ptrace = flags;
>
> ptrace_link(task, current);
> --
> 2.29.2
>