linux-kernel - Re: [PATCH v3] mm/hmm: bypass devmap pte when all pfn requested flags are fulfilled

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] [day] [month] [year] [list]

Message-ID: <20210830124049.GN1200268@ziepe.ca>
Date:   Mon, 30 Aug 2021 09:40:49 -0300
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     Li Zhijian <lizhijian@...fujitsu.com>, akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-rdma@...r.kernel.org, jglisse@...hat.com,
        hch@...radead.org, yishaih@...dia.com,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v3] mm/hmm: bypass devmap pte when all pfn requested
 flags are fulfilled

On Mon, Aug 30, 2021 at 05:42:32PM +0800, Li Zhijian wrote:
> Previously, we noticed the one rpma example was failed[1] since 36f30e486d,
> where it will use ODP feature to do RDMA WRITE between fsdax files.
> 
> After digging into the code, we found hmm_vma_handle_pte() will still
> return EFAULT even though all the its requesting flags has been
> fulfilled. That's because a DAX page will be marked as
> (_PAGE_SPECIAL | PAGE_DEVMAP) by pte_mkdevmap().
> 
> [1]: https://github.com/pmem/rpma/issues/1142
> 
> CC: stable@...r.kernel.org
> Fixes: 405506274922 ("mm/hmm: add missing call to hmm_pte_need_fault in HMM_PFN_SPECIAL handling")
> Signed-off-by: Li Zhijian <lizhijian@...fujitsu.com>
> 
> ---
> V3: adjust the checking order
> ---
>  mm/hmm.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)

Reviewed-by: Jason Gunthorpe <jgg@...dia.com>

Andrew, can you grab this please?

Thanks,
Jason