[PATCH v2 09/12] ptrace: Always take siglock in ptrace_resume

Eric W. Biederman
2022-04-29T21:48:34Z

Make code analysis simpler and future changes easier by
always taking siglock in ptrace_resume.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
kernel/ptrace.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 22041531adf6..c1c99e8be147 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -845,8 +845,6 @@ static long ptrace_get_rseq_configuration(struct task_struct *task,
static int ptrace_resume(struct task_struct *child, long request,
unsigned long data)
{
- bool need_siglock;
-
if (!valid_signal(data))
return -EIO;

@@ -882,18 +880,11 @@ static int ptrace_resume(struct task_struct *child, long request,
* Note that we need siglock even if ->exit_code = data and/or this
* status was not reported yet, the new status must not be cleared by
* wait_task_stopped() after resume.
- *
- * If data = 0 we do not care if wait_task_stopped() reports the old
- * status and clears the code too; this can't race with the tracee, it
- * takes siglock after resume.
*/
- need_siglock = data && !thread_group_empty(current);
- if (need_siglock)
- spin_lock_irq(&child->sighand->siglock);
+ spin_lock_irq(&child->sighand->siglock);
child->exit_code = data;
wake_up_state(child, __TASK_TRACED);
- if (need_siglock)
- spin_unlock_irq(&child->sighand->siglock);
+ spin_unlock_irq(&child->sighand->siglock);

return 0;
}
--
2.35.3