linux-kernel - Re: [PATCH] x86/mce: set MCE_IN_KERNEL

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]

Message-ID: <c5107413-3714-8aef-fa24-c0f46d705d68@huawei.com>
Date:   Wed, 24 May 2023 19:23:33 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Tony Luck <tony.luck@...el.com>, Borislav Petkov <bp@...en8.de>,
        Naoya Horiguchi <naoya.horiguchi@....com>
CC:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>, <x86@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        <linux-edac@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-mm@...ck.org>, <jane.chu@...cle.com>
Subject: Re: [PATCH] x86/mce: set MCE_IN_KERNEL_COPYIN for all MC-Safe Copy

Hi x86/mm maintainers, could you pick this up as it has be reviewed
by Naoya and Tony, many thanks.

On 2023/5/8 10:22, Kefeng Wang wrote:
> Both EX_TYPE_FAULT_MCE_SAFE and EX_TYPE_DEFAULT_MCE_SAFE exception
> fixup types are used to identify fixups which allow in kernel #MC
> recovery, that is the Machine Check Safe Copy.
> 
> For now, the MCE_IN_KERNEL_COPYIN flag is only set for EX_TYPE_COPY
> and EX_TYPE_UACCESS when copy from user, and corrupted page is
> isolated in this case, for MC-safe copy, memory_failure() is not
> always called, some places, like __wp_page_copy_user, copy_subpage,
> copy_user_gigantic_page and ksm_might_need_to_copy manually call
> memory_failure_queue() to cope with such unhandled error pages,
> recently coredump hwposion recovery support[1] is asked to do the
> same thing, and there are some other already existed MC-safe copy
> scenarios, eg, nvdimm, dm-writecache, dax, which has similar issue.
> 
> The best way to fix them is set MCE_IN_KERNEL_COPYIN to MCE_SAFE
> exception, then kill_me_never() will be queued to call memory_failure()
> in do_machine_check() to isolate corrupted page, which avoid calling
> memory_failure_queue() after every MC-safe copy return.
> 
> [1] https://lkml.kernel.org/r/20230417045323.11054-1-wangkefeng.wang@huawei.com
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>