linux-kernel - [PATCH] __ptrace_unlink: kill the obsolete "FIXME" code

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Message-ID: <20231121162650.GA6635@redhat.com>
Date:   Tue, 21 Nov 2023 17:26:50 +0100
From:   Oleg Nesterov <oleg@...hat.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     "Eric W. Biederman" <ebiederm@...ssion.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] __ptrace_unlink: kill the obsolete "FIXME" code

The corner case described by the comment is no longer possible after the
commit 7b3c36fc4c23 ("ptrace: fix task_join_group_stop() for the case when
current is traced"), task_join_group_stop() ensures that the new thread has
the correct signr in JOBCTL_STOP_SIGMASK regardless of ptrace.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 kernel/ptrace.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 443057bee87c..d6fc63458c76 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -145,20 +145,9 @@ void __ptrace_unlink(struct task_struct *child)
 	 */
 	if (!(child->flags & PF_EXITING) &&
 	    (child->signal->flags & SIGNAL_STOP_STOPPED ||
-	     child->signal->group_stop_count)) {
+	     child->signal->group_stop_count))
 		child->jobctl |= JOBCTL_STOP_PENDING;
 
-		/*
-		 * This is only possible if this thread was cloned by the
-		 * traced task running in the stopped group, set the signal
-		 * for the future reports.
-		 * FIXME: we should change ptrace_init_task() to handle this
-		 * case.
-		 */
-		if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
-			child->jobctl |= SIGSTOP;
-	}
-
 	/*
 	 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
 	 * @child in the butt.  Note that @resume should be used iff @child
-- 
2.25.1.362.g51ebf55