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From: Christian Brauner <christian.brauner@ubuntu.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-kernel@vger.kernel.org, libc-alpha@sourceware.org,
	alistair23@gmail.com, ebiederm@xmission.com, arnd@arndb.de,
	dalias@libc.org, torvalds@linux-foundation.org,
	adhemerval.zanella@linaro.org, fweimer@redhat.com,
	palmer@sifive.com, macro@wdc.com, zongbox@gmail.com,
	akpm@linux-foundation.org, viro@zeniv.linux.org.uk,
	hpa@zytor.com
Subject: Re: [PATCH v3 1/1] waitid: Add support for waiting for the current process group
Date: Wed, 14 Aug 2019 22:50:41 +0200
Message-ID: <20190814205040.d7shwe6u3jz6qmcc@wittgenstein> (raw)
In-Reply-To: <20190814160917.GG11595@redhat.com>

On Wed, Aug 14, 2019 at 06:09:17PM +0200, Oleg Nesterov wrote:
> On 08/14, Christian Brauner wrote:
> >
> > and a signal could come in between the system call that
> > retrieved the process gorup and the call to waitid that changes the
>                         ^^^^^
> > current process group.
> 
> I noticed this typo only because I spent 2 minutes or more trying to
> understand this sentence ;) But yes, a signal handler or another thread
> can change pgrp in between.
> 
> Reviewed-by: Oleg Nesterov <oleg@redhat.com>

Applied-to:
https://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git/log/?h=pidfd
on top of P_PIDFD changes (cf. [1]) with merge conflict resolved (cf. [2]).
(All changes on top of v5.3-rc1.)

Merged-into:
https://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git/log/?h=for-next
and should show up in linux-next tomorrow.

Thanks!
Christian

/* References */
[1]: https://lore.kernel.org/r/20190727222229.6516-2-christian@brauner.io
[2]: patch after resolved merge-conflict:
 kernel/exit.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index 64bb6893a37d..d2d74a7b81d1 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1596,10 +1596,13 @@ static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop,
 		break;
 	case P_PGID:
 		type = PIDTYPE_PGID;
-		if (upid <= 0)
+		if (upid < 0)
 			return -EINVAL;
 
-		pid = find_get_pid(upid);
+		if (upid)
+			pid = find_get_pid(upid);
+		else
+			pid = get_task_pid(current, PIDTYPE_PGID);
 		break;
 	case P_PIDFD:
 		type = PIDTYPE_PID;

  parent reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAKmqyKMJPQAOKn11xepzAwXOd4e9dU0Cyz=A0T-uMEgUp5yJjA@mail.gmail.com>
2019-08-14 11:38 ` [PATCH v1 0/1] waitid: process group enhancement christian.brauner
2019-08-14 11:38   ` [PATCH v1 1/1] waitid: Add support for waiting for the current process group christian.brauner
2019-08-14 12:29     ` Oleg Nesterov
2019-08-14 12:45       ` Christian Brauner
2019-08-14 12:50         ` Oleg Nesterov
2019-08-14 12:53           ` Christian Brauner
2019-08-14 13:07 ` [PATCH v2 0/1] waitid: process group enhancement Christian Brauner
2019-08-14 13:07   ` [PATCH v2 1/1] waitid: Add support for waiting for the current process group Christian Brauner
2019-08-14 14:19     ` Oleg Nesterov
2019-08-14 14:35       ` Christian Brauner
2019-08-14 15:27         ` Oleg Nesterov
2019-08-14 15:30           ` Christian Brauner
2019-08-14 15:43 ` [PATCH v3 0/1] waitid: process group enhancement Christian Brauner
2019-08-14 15:44   ` [PATCH v3 1/1] waitid: Add support for waiting for the current process group Christian Brauner
2019-08-14 16:09     ` Oleg Nesterov
2019-08-14 16:15       ` Christian Brauner
2019-08-14 16:34         ` Christian Brauner
2019-08-14 16:55           ` Rich Felker
2019-08-14 17:02             ` Christian Brauner
2019-08-14 17:06             ` Linus Torvalds
2019-08-14 18:00               ` Rich Felker
2019-08-14 20:50       ` Christian Brauner [this message]
2019-08-14 15:58   ` [PATCH v3 0/1] waitid: process group enhancement Rich Felker
2019-08-14 16:13     ` Christian Brauner

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