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Subject: Re: [PATCH v5] fault-injection: introduce kvmalloc fallback options
To:     Mikulas Patocka <mpatocka@redhat.com>
Cc:     Michal Hocko <mhocko@kernel.org>,
        Matthew Wilcox <willy@infradead.org>,
        David Miller <davem@davemloft.net>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        eric.dumazet@gmail.com, edumazet@google.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        mst@redhat.com, jasowang@redhat.com,
        virtualization@lists.linux-foundation.org, dm-devel@redhat.com,
        Vlastimil Babka <vbabka@suse.cz>
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From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <a11d5714-1d71-0be0-94f7-aa928b96d05f@infradead.org>
Date:   Wed, 25 Apr 2018 14:11:06 -0700
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On 04/25/2018 01:57 PM, Mikulas Patocka wrote:
> 
> 
> On Wed, 25 Apr 2018, Randy Dunlap wrote:
> 
>> On 04/25/2018 01:02 PM, Mikulas Patocka wrote:
>>>
>>>
>>> From: Mikulas Patocka <mpatocka@redhat.com>
>>> Subject: [PATCH v4] fault-injection: introduce kvmalloc fallback options
>>>
>>> This patch introduces a fault-injection option "kvmalloc_fallback". This
>>> option makes kvmalloc randomly fall back to vmalloc.
>>>
>>> Unfortunatelly, some kernel code has bugs - it uses kvmalloc and then
>>
>>   Unfortunately,
> 
> OK - here I fixed the typos:
> 
> 
> From: Mikulas Patocka <mpatocka@redhat.com>
> Subject: [PATCH] fault-injection: introduce kvmalloc fallback options
> 
> This patch introduces a fault-injection option "kvmalloc_fallback". This
> option makes kvmalloc randomly fall back to vmalloc.
> 
> Unfortunately, some kernel code has bugs - it uses kvmalloc and then
> uses DMA-API on the returned memory or frees it with kfree. Such bugs were
> found in the virtio-net driver, dm-integrity or RHEL7 powerpc-specific
> code. This options helps to test for these bugs.
> 
> The patch introduces a config option FAIL_KVMALLOC_FALLBACK_PROBABILITY.
> It can be enabled in distribution debug kernels, so that kvmalloc abuse
> can be tested by the users. The default can be overridden with
> "kvmalloc_fallback" parameter or in /sys/kernel/debug/kvmalloc_fallback/.
> 
> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
> 
> ---
>  Documentation/fault-injection/fault-injection.txt |    7 +++++
>  include/linux/fault-inject.h                      |    9 +++---
>  kernel/futex.c                                    |    2 -
>  lib/Kconfig.debug                                 |   15 +++++++++++
>  mm/failslab.c                                     |    2 -
>  mm/page_alloc.c                                   |    2 -
>  mm/util.c                                         |   30 ++++++++++++++++++++++
>  7 files changed, 60 insertions(+), 7 deletions(-)

Acked-by: Randy Dunlap <rdunlap@infradead.org> # Documentation and Kconfig only

thanks.
-- 
~Randy