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From: Ziran Zhang <zhangcoder@yeah.net>
To: Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	Valentin Schneider <vschneid@redhat.com>,
	K Prateek Nayak <kprateek.nayak@amd.com>,
	linux-kernel@vger.kernel.org, Ziran Zhang <zhangcoder@yeah.net>
Subject: [PATCH] sched: clarify ptrace's effect on task_struct->parent
Date: Thu, 10 Sep 2026 12:17:21 +0800	[thread overview]
Message-ID: <20260910041721.8135-1-zhangcoder@yeah.net> (raw)

The current comment for the parent field does not explain that it can be
temporarily replaced by the tracer when the task is being ptraced.

This can lead to confusion, so clarify the comment to document this
important behavior.

No functional change.

Signed-off-by: Ziran Zhang <zhangcoder@yeah.net>
---
 include/linux/sched.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 705970d07..977859a63 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1093,7 +1093,11 @@ struct task_struct {
 	/* Real parent process: */
 	struct task_struct __rcu	*real_parent;
 
-	/* Recipient of SIGCHLD, wait4() reports: */
+	/*
+	 * Recipient of SIGCHLD, wait4() reports. Normally the same as
+	 * real_parent, but temporarily replaced by the tracer while the
+	 * task is ptraced.
+	 */
 	struct task_struct __rcu	*parent;
 
 	/*
-- 
2.51.0


             reply	other threads:[~2026-09-10  4:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-10  4:17 Ziran Zhang [this message]
2026-09-10 12:54 ` Oleg Nesterov
2026-09-10 13:16   ` Ziran Zhang
2026-09-10 13:30 ` [PATCH v2] " Ziran Zhang

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