From: Oleg Nesterov <oleg@redhat.com>
To: Kirill Tkhai <ktkhai@odin.com>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Michal Hocko <mhocko@suse.cz>, Rik van Riel <riel@redhat.com>,
Ionut Alexa <ionut.m.alexa@gmail.com>,
Peter Hurley <peter@hurleysoftware.com>,
Kirill Tkhai <tkhai@yandex.ru>
Subject: Re: [PATCH RFC 09/13] exit: Use for_each_thread() in do_wait()
Date: Tue, 26 May 2015 21:46:13 +0200 [thread overview]
Message-ID: <20150526194613.GC6978@redhat.com> (raw)
In-Reply-To: <1432575941.6866.42.camel@odin.com>
On 05/25, Kirill Tkhai wrote:
>
> Refactoring, no functionality change.
Hmm. unless I missed something this change is wrong.
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -1538,8 +1538,7 @@ static long do_wait(struct wait_opts *wo)
>
> set_current_state(TASK_INTERRUPTIBLE);
> read_lock(&tasklist_lock);
> - tsk = current;
> - do {
> + for_each_thread(current, tsk) {
> retval = do_wait_thread(wo, tsk);
> if (retval)
> goto end;
> @@ -1550,7 +1549,7 @@ static long do_wait(struct wait_opts *wo)
>
> if (wo->wo_flags & __WNOTHREAD)
> break;
> - } while_each_thread(current, tsk);
> + }
Please note the __WNOTHREAD check. This is the rare case when we
actually want while_each_thread() (although it should die anyway).
for_each_thread() always starts from ->group_leader, but we need
to start from "current" first.
Oleg.
next prev parent reply other threads:[~2015-05-26 19:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20150525162722.5171.15901.stgit@pro>
2015-05-25 17:44 ` [PATCH RFC 01/13] exit: Clarify choice of new parent in forget_original_parent() Kirill Tkhai
2015-05-25 17:44 ` [PATCH RFC 02/13] rwlock_t: Implement double_write_{,un}lock() Kirill Tkhai
2015-05-25 17:44 ` [PATCH RFC 03/13] pid_ns: Implement rwlock_t pid_ns::cr_lock for locking child_reaper Kirill Tkhai
2015-05-25 17:44 ` [PATCH RFC 04/13] exit: Small refactoring mm_update_next_owner() Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 05/13] fs: Refactoring in get_children_pid() Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 06/13] core: Add rwlock_t task_list::kin_lock Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 07/13] kin_lock: Implement helpers for kin_lock locking Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 08/13] core: Use kin_lock synchronizations between parent and child and for thread group Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 09/13] exit: Use for_each_thread() in do_wait() Kirill Tkhai
2015-05-26 19:46 ` Oleg Nesterov [this message]
2015-05-27 9:33 ` Kirill Tkhai
2015-05-27 9:42 ` Kirill Tkhai
2015-05-25 17:45 ` [PATCH RFC 10/13] exit: Add struct wait_opts's member held_lock and use it for tasklist_lock Kirill Tkhai
2015-05-25 17:46 ` [PATCH RFC 11/13] exit: Syncronize on kin_lock while do_notify_parent() Kirill Tkhai
2015-05-25 17:46 ` [PATCH RFC 12/13] exit: Delete write dependence on tasklist_lock in exit_notify() Kirill Tkhai
2015-05-25 17:46 ` [PATCH RFC 13/13] core: Nest tasklist_lock into task_struct::kin_lock Kirill Tkhai
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