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From: ebiederm@xmission.com (Eric W. Biederman)
To: LKML <linux-kernel@vger.kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH v1 3/4] exec: Remove BUG_ON(has_group_leader_pid)
Date: Tue, 28 Apr 2020 16:53:31 -0500	[thread overview]
Message-ID: <87zhav5lb8.fsf_-_@x220.int.ebiederm.org> (raw)
In-Reply-To: <87mu6v70in.fsf_-_@x220.int.ebiederm.org> (Eric W. Biederman's message of "Tue, 28 Apr 2020 16:39:44 -0500")


With the introduction of exchange_tids thread_group_leader and
has_group_leader_pid have become equivalent.  Further at this point in the
code a thread group has exactly two threads, the previous thread_group_leader
that is waiting to be reaped and tsk.  So we know it is impossible for tsk to
be the thread_group_leader.

This is also the last user of has_group_leader_pid so removing this check
will allow has_group_leader_pid to be removed.

So remove the "BUG_ON(has_group_leader_pid)" that will never fire.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 fs/exec.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/exec.c b/fs/exec.c
index 9b60f927afd7..6ab1c19d84fa 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1176,7 +1176,6 @@ static int de_thread(struct task_struct *tsk)
 		tsk->start_boottime = leader->start_boottime;
 
 		BUG_ON(!same_thread_group(leader, tsk));
-		BUG_ON(has_group_leader_pid(tsk));
 		/*
 		 * An exec() starts a new thread group with the
 		 * TGID of the previous thread group. Rehash the
-- 
2.20.1


  parent reply	other threads:[~2020-04-28 21:56 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-19 14:10 [PATCH v12 0/7] proc: modernize proc to support multiple private instances Alexey Gladkov
2020-04-19 14:10 ` [PATCH v12 1/7] proc: rename struct proc_fs_info to proc_fs_opts Alexey Gladkov
2020-04-19 14:10 ` [PATCH v12 2/7] proc: allow to mount many instances of proc in one pid namespace Alexey Gladkov
2020-04-23 11:28   ` [PATCH v13 " Alexey Gladkov
2020-04-23 12:16     ` Eric W. Biederman
2020-04-23 20:01       ` Alexey Gladkov
2020-04-19 14:10 ` [PATCH v12 3/7] proc: instantiate only pids that we can ptrace on 'hidepid=4' mount option Alexey Gladkov
2020-04-19 14:10 ` [PATCH v12 4/7] proc: add option to mount only a pids subset Alexey Gladkov
2020-04-19 14:10 ` [PATCH v12 5/7] docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior Alexey Gladkov
2020-04-19 14:10 ` [PATCH v12 6/7] proc: use human-readable values for hidepid Alexey Gladkov
2020-04-19 14:10 ` [PATCH v12 7/7] proc: use named enums for better readability Alexey Gladkov
     [not found] ` <87ftcv1nqe.fsf@x220.int.ebiederm.org>
2020-04-23 17:54   ` [PATCH v2 0/2] proc: Calling proc_flush_task exactly once per task Oleg Nesterov
2020-04-23 19:38     ` Eric W. Biederman
2020-04-23 19:39   ` [PATCH v2 1/2] proc: Use PIDTYPE_TGID in next_tgid Eric W. Biederman
2020-04-24 17:29     ` Oleg Nesterov
2020-04-23 19:39   ` [PATCH v2 2/2] proc: Ensure we see the exit of each process tid exactly Eric W. Biederman
2020-04-23 20:28     ` Linus Torvalds
2020-04-24  3:33       ` Eric W. Biederman
2020-04-24 18:02         ` Linus Torvalds
2020-04-24 18:46           ` Linus Torvalds
2020-04-24 19:51           ` Eric W. Biederman
2020-04-24 20:10             ` Linus Torvalds
2020-04-24 17:39     ` Oleg Nesterov
2020-04-24 18:10       ` Eric W. Biederman
2020-04-24 20:50       ` [PATCH] proc: Put thread_pid in release_task not proc_flush_pid Eric W. Biederman
     [not found]       ` <87mu6ymkea.fsf_-_@x220.int.ebiederm.org>
     [not found]         ` <87blnemj5t.fsf_-_@x220.int.ebiederm.org>
2020-04-26 17:22           ` [PATCH v3 2/6] posix-cpu-timers: Use PIDTYPE_TGID to simplify the logic in lookup_task Oleg Nesterov
2020-04-27 11:51             ` Eric W. Biederman
2020-04-28 18:03               ` Oleg Nesterov
2020-04-27 10:32           ` Thomas Gleixner
2020-04-27 19:46             ` Eric W. Biederman
     [not found]         ` <875zdmmj4y.fsf_-_@x220.int.ebiederm.org>
2020-04-26 17:40           ` [PATCH v3 3/6] rculist: Add hlist_swap_before_rcu Linus Torvalds
2020-04-27 14:28             ` Eric W. Biederman
2020-04-27 20:27               ` Linus Torvalds
2020-04-28 12:16                 ` [PATCH v4 0/2] proc: Ensure we see the exit of each process tid exactly Eric W. Biederman
2020-04-28 12:18                   ` [PATCH v4 1/2] rculist: Add hlists_swap_heads_rcu Eric W. Biederman
2020-04-28 12:19                   ` [PATCH v4 2/2] proc: Ensure we see the exit of each process tid exactly once Eric W. Biederman
2020-04-28 16:53                   ` [PATCH v4 0/2] proc: Ensure we see the exit of each process tid exactly Linus Torvalds
2020-04-28 17:55                     ` Eric W. Biederman
2020-04-28 18:55                     ` Eric W. Biederman
2020-04-28 19:36                       ` Linus Torvalds
2020-04-28 18:05                   ` Oleg Nesterov
2020-04-28 18:54                     ` Eric W. Biederman
2020-04-28 21:39                     ` [PATCH v1 0/4] signal: Removing has_group_leader_pid Eric W. Biederman
2020-04-28 21:45                       ` [PATCH v1 1/4] posix-cpu-timer: Tidy up group_leader logic in lookup_task Eric W. Biederman
2020-04-28 21:48                       ` [PATCH 2/4] posix-cpu-timer: Unify the now redundant code " Eric W. Biederman
2020-04-28 21:53                       ` Eric W. Biederman [this message]
2020-04-28 21:56                       ` [PATCH v4 4/4] signal: Remove has_group_leader_pid Eric W. Biederman
2020-04-30 11:54                       ` [PATCH v1 0/3] posix-cpu-timers: Use pids not tasks in lookup Eric W. Biederman
2020-04-30 11:55                         ` [PATCH v1 1/3] posix-cpu-timers: Extend rcu_read_lock removing task_struct references Eric W. Biederman
2020-04-30 11:56                         ` [PATCH v1 2/3] posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type Eric W. Biederman
2020-04-30 11:56                         ` [PATCH v1 3/3] posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock Eric W. Biederman
     [not found]         ` <87h7x6mj6h.fsf_-_@x220.int.ebiederm.org>
2020-04-27  9:43           ` [PATCH v3 1/6] posix-cpu-timers: Always call __get_task_for_clock holding rcu_read_lock Thomas Gleixner
2020-04-27 11:53             ` Eric W. Biederman
     [not found]         ` <87r1w8ete7.fsf@x220.int.ebiederm.org>
2020-04-27 20:23           ` [PATCH v3] proc: Ensure we see the exit of each process tid exactly Eric W. Biederman

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