From: Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Konstantin Khlebnikov
<khlebnikov-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org>,
Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>,
KAMEZAWA Hiroyuki
<kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>,
KOSAKI Motohiro
<kosaki.motohiro-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
Cc: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Roman Gushchin <klamm-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org>,
Nikita Vetoshkin
<nekto0n-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org>,
Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
Subject: memcg && uaccess (Was: [PATCH 1/2] kernel/fork: handle put_user errors for CLONE_CHILD_SETTID/CLEARTID)
Date: Fri, 6 Feb 2015 21:32:46 +0100 [thread overview]
Message-ID: <20150206203246.GA16924@redhat.com> (raw)
In-Reply-To: <20150206195529.GA15517-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Add cc's.
On 02/06, Oleg Nesterov wrote:
>
> And in fact I think that this is not set_child_tid/etc-specific. Perhaps
> I am totally confused, but I think that put_user() simply should not fail
> this way. Say, why a syscall should return -EFAULT if memory allocation
> "silently" fails? Confused.
Seriously. I must have missed something, but I can't understand 519e52473eb
"mm: memcg: enable memcg OOM killer only for user faults".
The changelog says:
System calls and kernel faults (uaccess, gup) can handle an out of
memory situation gracefully and just return -ENOMEM.
How can a system call know it should return -ENOMEM if put_user() can only
return -EFAULT ?
Oleg.
WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: linux-api@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Roman Gushchin <klamm@yandex-team.ru>,
Nikita Vetoshkin <nekto0n@yandex-team.ru>,
Pavel Emelyanov <xemul@parallels.com>
Subject: memcg && uaccess (Was: [PATCH 1/2] kernel/fork: handle put_user errors for CLONE_CHILD_SETTID/CLEARTID)
Date: Fri, 6 Feb 2015 21:32:46 +0100 [thread overview]
Message-ID: <20150206203246.GA16924@redhat.com> (raw)
In-Reply-To: <20150206195529.GA15517@redhat.com>
Add cc's.
On 02/06, Oleg Nesterov wrote:
>
> And in fact I think that this is not set_child_tid/etc-specific. Perhaps
> I am totally confused, but I think that put_user() simply should not fail
> this way. Say, why a syscall should return -EFAULT if memory allocation
> "silently" fails? Confused.
Seriously. I must have missed something, but I can't understand 519e52473eb
"mm: memcg: enable memcg OOM killer only for user faults".
The changelog says:
System calls and kernel faults (uaccess, gup) can handle an out of
memory situation gracefully and just return -ENOMEM.
How can a system call know it should return -ENOMEM if put_user() can only
return -EFAULT ?
Oleg.
next prev parent reply other threads:[~2015-02-06 20:32 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-06 16:23 [PATCH 1/2] kernel/fork: handle put_user errors for CLONE_CHILD_SETTID/CLEARTID Konstantin Khlebnikov
2015-02-06 16:23 ` [PATCH 2/2] kernel/fork: handle put_user errors for CLONE_PARENT_SETTID Konstantin Khlebnikov
2015-02-06 16:23 ` Konstantin Khlebnikov
2015-02-06 20:49 ` Linus Torvalds
2015-02-06 20:49 ` Linus Torvalds
[not found] ` <CA+55aFxBuf-0UkoYCrwH_vNsWFnUkFOz5c9O_Mswe_w0BTkqbQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-02-06 21:07 ` Oleg Nesterov
2015-02-06 21:07 ` Oleg Nesterov
2015-02-06 21:13 ` Konstantin Khlebnikov
2015-02-06 21:55 ` Andy Lutomirski
[not found] ` <CALYGNiMv021=WC2uXsjo5zT8JwewweZUDdk0x8FGHh9V5j6bFQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-02-06 22:10 ` Linus Torvalds
2015-02-06 22:10 ` Linus Torvalds
2015-02-06 19:44 ` [PATCH 1/2] kernel/fork: handle put_user errors for CLONE_CHILD_SETTID/CLEARTID Oleg Nesterov
2015-02-06 19:44 ` Oleg Nesterov
[not found] ` <20150206194405.GA13960-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-02-06 19:55 ` Oleg Nesterov
2015-02-06 19:55 ` Oleg Nesterov
[not found] ` <20150206195529.GA15517-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-02-06 20:27 ` Konstantin Khlebnikov
2015-02-06 20:27 ` Konstantin Khlebnikov
2015-02-06 20:32 ` Oleg Nesterov [this message]
2015-02-06 20:32 ` memcg && uaccess (Was: [PATCH 1/2] kernel/fork: handle put_user errors for CLONE_CHILD_SETTID/CLEARTID) Oleg Nesterov
[not found] ` <20150206203246.GA16924-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-02-10 16:19 ` Johannes Weiner
2015-02-10 16:19 ` Johannes Weiner
2015-02-10 19:47 ` Oleg Nesterov
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