From: Michal Hocko <mhocko@kernel.org>
To: Nadav Amit <namit@vmware.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@linux-foundation.org>,
stable@vger.kernel.org
Subject: Re: [PATCH] mm: respect arch_dup_mmap() return value
Date: Thu, 23 Aug 2018 10:57:14 +0200 [thread overview]
Message-ID: <20180823085714.GY29735@dhcp22.suse.cz> (raw)
In-Reply-To: <20180823051229.211856-1-namit@vmware.com>
On Wed 22-08-18 22:12:29, Nadav Amit wrote:
> Commit d70f2a14b72a4 ("include/linux/sched/mm.h: uninline
> mmdrop_async(), etc") ignored the return value of arch_dup_mmap(). As a
> result, on x86, a failure to duplicate the LDT (e.g., due to memory
> allocation error), would leave the duplicated memory mapping in an
> inconsistent state.
>
> Fix by regarding the return value, as it was before the change.
Ohh, well spotted! I have a vague recollection I didn't really like the
patch. For other reasons. I didn't get to review it properly back then
because I didn't have much time and I didn't have a high motivation
because I simple disagreed with the patch.
> Fixes: d70f2a14b72a4 ("include/linux/sched/mm.h: uninline mmdrop_async(), etc")
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: stable@vger.kernel.org
> Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Thanks!
> ---
> kernel/fork.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 1b27babc4c78..4527d1d331de 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -549,8 +549,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
> goto out;
> }
> /* a new mm has just been created */
> - arch_dup_mmap(oldmm, mm);
> - retval = 0;
> + retval = arch_dup_mmap(oldmm, mm);
> out:
> up_write(&mm->mmap_sem);
> flush_tlb_mm(oldmm);
> --
> 2.17.1
>
--
Michal Hocko
SUSE Labs
prev parent reply other threads:[~2018-08-23 8:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-23 5:12 [PATCH] mm: respect arch_dup_mmap() return value Nadav Amit
2018-08-23 8:57 ` Michal Hocko [this message]
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