From: Oleg Nesterov <oleg@redhat.com>
To: Maninder Singh <maninder1.s@samsung.com>
Cc: akpm@linux-foundation.org, mhocko@suse.cz, peterz@infradead.org,
mingo@kernel.org, riel@redhat.com, ionut.m.alexa@gmail.com,
peter@hurleysoftware.com, linux-kernel@vger.kernel.org,
"v.narang@samsung.com" <v.narang@samsung.com>,
AKHILESH KUMAR <akhilesh.k@samsung.com>
Subject: Re: [EDT][PATCH] kernel/exit.c : Fix missing read_unlock
Date: Thu, 21 May 2015 20:16:16 +0200 [thread overview]
Message-ID: <20150521181616.GA18981@redhat.com> (raw)
In-Reply-To: <670017389.505251432184399737.JavaMail.weblogic@ep2mlwas07b>
On 05/21, Maninder Singh wrote:
>
> EP-F6AA0618C49C4AEDA73BFF1B39950BAB
> Hi,
>
> From: Maninder Singh <maninder1.s@samsung.com>
>
> Subject: [PATCH 1/1] kernel/exit.c : Fix missing task_unlock
>
> This patch adds missing read_unlock if do_wait_thread or ptrace_do_wait
> returns non zero.
Confused...
wait_consider_task() should drop tasklist_lock if it returns non-zero?
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -1486,12 +1486,16 @@ repeat:
> tsk = current;
> do {
> retval = do_wait_thread(wo, tsk);
> - if (retval)
> + if (retval) {
> + read_unlock(&tasklist_lock);
> goto end;
> + }
>
> retval = ptrace_do_wait(wo, tsk);
> - if (retval)
> + if (retval) {
> + read_unlock(&tasklist_lock);
> goto end;
> + }
Well, the patch is obviously wrong. Because, again, tasklist_lock was
already unlocked if (say) wait_task_zombie() reaps a child.
If you think there is a case which forgets to unlock, please tell us
more.
Oleg.
next prev parent reply other threads:[~2015-05-21 18:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-21 5:00 [EDT][PATCH] kernel/exit.c : Fix missing read_unlock Maninder Singh
2015-05-21 6:03 ` Ingo Molnar
2015-05-21 10:32 ` Frans Klaver
2015-05-21 10:56 ` Ingo Molnar
2015-05-21 11:39 ` Frans Klaver
2015-05-21 18:16 ` Oleg Nesterov [this message]
-- strict thread matches above, loose matches on Subject: below --
2015-05-21 6:34 Maninder Singh
2015-05-21 10:58 ` Ingo Molnar
2015-05-21 11:44 Maninder Singh
2015-05-22 3:36 Maninder Singh
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