From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] fs, elf: drop MAP_FIXED usage from elf_map
Date: Wed, 18 Apr 2018 13:55:46 +0200 [thread overview]
Message-ID: <20180418115546.GZ17484@dhcp22.suse.cz> (raw)
In-Reply-To: <201804182043.JFH90161.LStOOMFFOJQHVF@I-love.SAKURA.ne.jp>
On Wed 18-04-18 20:43:11, Tetsuo Handa wrote:
> Michal Hocko wrote:
> > > Don't complain if IS_ERR_VALUE(),
> >
> > this is simply wrong. We do want to warn on the failure because this is
> > when the actual clash happens. We should just warn on EEXIST.
>
> >From 25442cdd31aa5cc8522923a0153a77dfd2ebc832 Mon Sep 17 00:00:00 2001
> From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Date: Wed, 18 Apr 2018 20:38:15 +0900
> Subject: [PATCH] fs, elf: don't complain MAP_FIXED_NOREPLACE unless -EEXIST
> error.
>
> Commit 4ed28639519c7bad ("fs, elf: drop MAP_FIXED usage from elf_map") is
> printing spurious messages under memory pressure due to map_addr == -ENOMEM.
>
> 9794 (a.out): Uhuuh, elf segment at 00007f2e34738000(fffffffffffffff4) requested but the memory is mapped already
> 14104 (a.out): Uhuuh, elf segment at 00007f34fd76c000(fffffffffffffff4) requested but the memory is mapped already
> 16843 (a.out): Uhuuh, elf segment at 00007f930ecc7000(fffffffffffffff4) requested but the memory is mapped already
>
> Complain only if -EEXIST, and use %px for printing the address.
Yes this is better. But...
[...]
> - if ((type & MAP_FIXED_NOREPLACE) && BAD_ADDR(map_addr))
> - pr_info("%d (%s): Uhuuh, elf segment at %p requested but the memory is mapped already\n",
> - task_pid_nr(current), current->comm,
> - (void *)addr);
> + if ((type & MAP_FIXED_NOREPLACE) && map_addr == -EEXIST)
... please use PTR_ERR(map_addr) == -EEXIST
then you can add
Acked-by: Michal Hocko <mhocko@suse.com>
> + pr_info("%d (%s): Uhuuh, elf segment at %px requested but the memory is mapped already\n",
> + task_pid_nr(current), current->comm, (void *)addr);
>
> return(map_addr);
> }
> --
> 1.8.3.1
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-04-18 11:55 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-13 9:25 [PATCH v2 0/2] mm: introduce MAP_FIXED_SAFE Michal Hocko
2017-12-13 9:25 ` [PATCH 1/2] " Michal Hocko
2017-12-13 12:50 ` Matthew Wilcox
2017-12-13 13:01 ` Michal Hocko
2017-12-13 9:25 ` [PATCH 2/2] fs, elf: drop MAP_FIXED usage from elf_map Michal Hocko
2017-12-16 0:49 ` [2/2] " Andrei Vagin
2017-12-18 9:13 ` Michal Hocko
2017-12-18 18:12 ` Andrei Vagin
2017-12-18 18:49 ` [PATCH] mm: don't use the same value for MAP_FIXED_SAFE and MAP_SYNC Andrei Vagin
2017-12-18 20:41 ` Michal Hocko
2018-04-18 10:51 ` [PATCH 2/2] fs, elf: drop MAP_FIXED usage from elf_map Tetsuo Handa
2018-04-18 11:33 ` Michal Hocko
2018-04-18 11:43 ` Tetsuo Handa
2018-04-18 11:55 ` Michal Hocko [this message]
2018-04-18 14:07 ` [PATCH v2] fs, elf: don't complain MAP_FIXED_NOREPLACE unless -EEXIST error Tetsuo Handa
2018-04-19 5:57 ` Michal Hocko
2017-12-13 9:31 ` [PATCH 1/2] mmap.2: document new MAP_FIXED_SAFE flag Michal Hocko
2017-12-13 9:31 ` [PATCH 2/2] mmap.2: MAP_FIXED updated documentation Michal Hocko
2017-12-13 12:55 ` Pavel Machek
2017-12-13 13:03 ` Cyril Hrubis
2017-12-13 13:04 ` Michal Hocko
2017-12-13 13:09 ` Pavel Machek
2017-12-13 13:16 ` Michal Hocko
2017-12-13 13:21 ` Pavel Machek
2017-12-13 13:35 ` Michal Hocko
2017-12-13 14:40 ` Cyril Hrubis
2017-12-13 23:19 ` Kees Cook
2017-12-14 7:07 ` Michal Hocko
2017-12-18 19:12 ` Michael Kerrisk (man-pages)
2017-12-18 20:19 ` Kees Cook
2017-12-18 20:33 ` Matthew Wilcox
2017-12-21 12:38 ` Michael Ellerman
2017-12-21 14:59 ` known bad patch in -mm tree was " Pavel Machek
2017-12-21 15:08 ` Michal Hocko
2017-12-21 22:24 ` Andrew Morton
2017-12-22 0:06 ` Michael Ellerman
2017-12-14 2:52 ` Jann Horn
2017-12-14 5:28 ` John Hubbard
2017-12-14 23:06 ` John Hubbard
2017-12-14 23:10 ` Jann Horn
2017-12-13 12:25 ` [PATCH v2 0/2] mm: introduce MAP_FIXED_SAFE Matthew Wilcox
2017-12-13 12:34 ` Michal Hocko
2017-12-13 17:13 ` Kees Cook
2017-12-15 9:02 ` Michael Ellerman
2017-12-14 0:32 ` Andrew Morton
2017-12-14 1:35 ` David Goldblatt
2017-12-14 1:42 ` David Goldblatt
2017-12-14 12:44 ` Edward Napierala
2017-12-14 13:15 ` Michal Hocko
2017-12-14 14:54 ` Edward Napierala
2017-12-19 12:40 ` David Laight
2017-12-19 12:46 ` Michal Hocko
-- strict thread matches above, loose matches on Subject: below --
2017-11-29 14:42 [PATCH " Michal Hocko
2017-11-29 14:42 ` [PATCH 2/2] fs, elf: drop MAP_FIXED usage from elf_map Michal Hocko
2017-11-29 17:45 ` Khalid Aziz
2018-05-29 22:21 ` Mike Kravetz
2018-05-30 8:02 ` Michal Hocko
2018-05-30 15:00 ` Mike Kravetz
2018-05-30 16:25 ` Michal Hocko
2018-05-31 0:51 ` Mike Kravetz
2018-05-31 9:24 ` Michal Hocko
2018-05-31 21:46 ` Mike Kravetz
2017-11-16 10:18 Michal Hocko
2017-11-16 10:19 ` [PATCH 2/2] fs, elf: drop MAP_FIXED usage from elf_map Michal Hocko
2017-11-17 0:30 ` Kees Cook
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