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

Commit Message

Eric W. Biederman April 29, 2022, 9:48 p.m. UTC

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

Signed-off-by: "Eric W. Biederman" <[e-mail]>
---
 kernel/ptrace.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

Patch

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;
 }