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From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Roland McGrath <roland@hack.frob.com>, Tejun Heo <tj@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Pedro Alves <palves@redhat.com>,
	Jan Kratochvil <jan.kratochvil@redhat.com>
Subject: [PATCH 2/2] ptrace: task_stopped_code(ptrace => true) can't see TASK_STOPPED task
Date: Thu, 19 Nov 2015 19:47:52 +0100	[thread overview]
Message-ID: <20151119184752.GC19061@redhat.com> (raw)
In-Reply-To: <20151119184709.GA19061@redhat.com>

task_stopped_code()->task_is_stopped_or_traced() doesn't look right,
the traced task must never be TASK_STOPPED.

We can not add WARN_ON(task_is_stopped(p)), but this is only because
do_wait() can race with PTRACE_ATTACH from another thread.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 kernel/exit.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index c090738..fc7b4ec 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1127,7 +1127,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 static int *task_stopped_code(struct task_struct *p, bool ptrace)
 {
 	if (ptrace) {
-		if (task_is_stopped_or_traced(p) &&
+		if (task_is_traced(p) &&
 		    !(p->jobctl & JOBCTL_LISTENING))
 			return &p->exit_code;
 	} else {
-- 
1.5.5.1



  parent reply	other threads:[~2015-11-19 18:47 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-09 15:12 ptrace() hangs on attempt to seize/attach stopped & frozen task Andrey Ryabinin
2015-11-09 18:55 ` Oleg Nesterov
2015-11-09 18:02   ` Tejun Heo
2015-11-10 20:20     ` Oleg Nesterov
2015-11-16 18:45       ` Tejun Heo
2015-11-17 19:34         ` Oleg Nesterov
2015-11-17 18:57           ` Tejun Heo
2015-11-19 16:49           ` Pedro Alves
2015-11-19 17:47             ` Oleg Nesterov
2015-11-19 18:08               ` Pedro Alves
2015-11-10 20:20   ` Oleg Nesterov
2015-11-19 18:47 ` [PATCH 0/2] (Was: ptrace() hangs on attempt to seize/attach stopped & frozen task) Oleg Nesterov
2015-11-19 18:47   ` [PATCH 1/2] ptrace: make wait_on_bit(JOBCTL_TRAPPING_BIT) in ptrace_attach() killable Oleg Nesterov
2015-11-23 23:05     ` Tejun Heo
2015-11-19 18:47   ` Oleg Nesterov [this message]
2015-11-23 23:15     ` [PATCH 2/2] ptrace: task_stopped_code(ptrace => true) can't see TASK_STOPPED task Tejun Heo

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