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Date:   Tue, 26 Sep 2023 13:49:27 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Edward AD <twuufnxlz@gmail.com>
Cc:     conor@kernel.org,
        syzbot+8d2757d62d403b2d9275@syzkaller.appspotmail.com,
        jirislaby@kernel.org, linux-kernel@vger.kernel.org,
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        aou@eecs.berkeley.edu, guoren@kernel.org, alexghiti@rivosinc.com,
        liushixin2@huawei.com, linux-riscv@lists.infradead.org
Subject: Re: [PATCH] riscv: fix out of bounds in walk_stackframe
Message-ID: <2023092617-polish-modify-3acb@gregkh>
References: <0000000000000170df0605ccf91a@google.com>
 <20230926114343.1061739-2-twuufnxlz@gmail.com>
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On Tue, Sep 26, 2023 at 07:43:44PM +0800, Edward AD wrote:
> Increase the check on the frame after assigning its value. This is to prevent 
> frame access from crossing boundaries.
> 
> Closes: https://lore.kernel.org/all/20230926105949.1025995-2-twuufnxlz@gmail.com/
> Fixes: 5d8544e2d007 ("RISC-V: Generic library routines and assembly")
> Reported-and-tested-by: syzbot+8d2757d62d403b2d9275@syzkaller.appspotmail.com
> Link: https://lore.kernel.org/all/0000000000000170df0605ccf91a@google.com/T/
> Signed-off-by: Edward AD <twuufnxlz@gmail.com>
> ---
>  arch/riscv/kernel/stacktrace.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
> index 64a9c093aef9..53bd18672329 100644
> --- a/arch/riscv/kernel/stacktrace.c
> +++ b/arch/riscv/kernel/stacktrace.c
> @@ -54,6 +54,8 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
>  			break;
>  		/* Unwind stack frame */
>  		frame = (struct stackframe *)fp - 1;
> +		if (!virt_addr_valid(frame))
> +			break;
>  		sp = fp;
>  		if (regs && (regs->epc == pc) && (frame->fp & 0x7)) {
>  			fp = frame->ra;
> -- 
> 2.25.1
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- You have marked a patch with a "Fixes:" tag for a commit that is in an
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  follow the documented rules in the
  Documetnation/process/stable-kernel-rules.rst file for how to resolve
  this.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
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thanks,

greg k-h's patch email bot