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Message-ID: <06c11112-db64-40ed-bb96-fa02b590a432@I-love.SAKURA.ne.jp>
Date: Tue, 5 Mar 2024 20:31:13 +0900
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Subject: Re: [PATCH v2] x86: disable non-instrumented version of copy_mc when
 KMSAN is enabled
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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: LKML <linux-kernel@vger.kernel.org>,
        the arch/x86 maintainers <x86@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
References: <3b7dbd88-0861-4638-b2d2-911c97a4cadf@I-love.SAKURA.ne.jp>
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Ping?

This is current top crasher.
I hope this patch is applied before the merge window opens.

On 2024/03/02 7:52, Tetsuo Handa wrote:
> dump_emit_page() caused a false-positive KMSAN warning, for
> memcpy_from_iter_mc() is called via iterate_bvec() by setting "struct
> iov_iter"->copy_mc to true.
> 
> Fallback to memcpy()/copy_user_generic() when KMSAN is enabled.
> 
> Reported-by: syzbot <syzbot+d7521c1e3841ed075a42@syzkaller.appspotmail.com>
> Closes: https://syzkaller.appspot.com/bug?extid=d7521c1e3841ed075a42
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Tested-by: syzbot <syzbot+d7521c1e3841ed075a42@syzkaller.appspotmail.com>
> Reviewed-by: Alexander Potapenko <glider@google.com>
> ---
> Changes in v2:
>   Update description.
> 
>  arch/x86/lib/copy_mc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)