linux-kernel - Re: [PATCH 1/3] mm: Check if mmu notifier callbacks are allowed to fail

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 23 Nov 2018 12:15:57 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     Daniel Vetter <daniel.vetter@...ll.ch>
Cc:     LKML <linux-kernel@...r.kernel.org>, Linux MM <linux-mm@...ck.org>,
        Intel Graphics Development <intel-gfx@...ts.freedesktop.org>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Christian König <christian.koenig@....com>,
        David Rientjes <rientjes@...gle.com>,
        Jérôme Glisse <jglisse@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Daniel Vetter <daniel.vetter@...el.com>
Subject: Re: [PATCH 1/3] mm: Check if mmu notifier callbacks are allowed to
 fail

On Thu 22-11-18 17:51:04, Daniel Vetter wrote:
> Just a bit of paranoia, since if we start pushing this deep into
> callchains it's hard to spot all places where an mmu notifier
> implementation might fail when it's not allowed to.

What does WARN give you more than the existing pr_info? Is really
backtrace that interesting?

> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: Michal Hocko <mhocko@...e.com>
> Cc: "Christian König" <christian.koenig@....com>
> Cc: David Rientjes <rientjes@...gle.com>
> Cc: Daniel Vetter <daniel.vetter@...ll.ch>
> Cc: "Jérôme Glisse" <jglisse@...hat.com>
> Cc: linux-mm@...ck.org
> Cc: Paolo Bonzini <pbonzini@...hat.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@...el.com>
> ---
>  mm/mmu_notifier.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
> index 5119ff846769..59e102589a25 100644
> --- a/mm/mmu_notifier.c
> +++ b/mm/mmu_notifier.c
> @@ -190,6 +190,8 @@ int __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
>  				pr_info("%pS callback failed with %d in %sblockable context.\n",
>  						mn->ops->invalidate_range_start, _ret,
>  						!blockable ? "non-" : "");
> +				WARN(blockable,"%pS callback failure not allowed\n",
> +				     mn->ops->invalidate_range_start);
>  				ret = _ret;
>  			}
>  		}
> -- 
> 2.19.1
> 

-- 
Michal Hocko
SUSE Labs