linux-kernel - Re: [External] Re: [PATCH] riscv/fault: Dump user opcode bytes on fatal faults

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAEEQ3wm4Ax4v63QVb7NtQp=-HxbKZNAUsQwevBzDs3sX4+pu9w@mail.gmail.com>
Date:   Wed, 29 Mar 2023 15:35:26 +0800
From:   运辉崔 <cuiyunhui@...edance.com>
To:     Conor Dooley <conor.dooley@...rochip.com>
Cc:     Conor Dooley <conor@...nel.org>, paul.walmsley@...ive.com,
        palmer@...belt.com, aou@...s.berkeley.edu,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [External] Re: [PATCH] riscv/fault: Dump user opcode bytes on
 fatal faults

Hi Conor,

On Wed, Mar 29, 2023 at 2:25 PM Conor Dooley <conor.dooley@...rochip.com> wrote:

>
> Right, I'm trying to figure out of this is another bug in the kernel -
> if you don't have "fd" in riscv,isa in your devicetree then, even if
> CONFIG_FPU is set, none of the FPU code is meant to run, right?

yeah, CONFIG_FPU is set.
In the problem I encountered, the init to be executed in user mode
contained floating-point instructions, which caused an exception.

> What would be nice to have is what the new show_opcodes() function will
> look like ;)

After printing the contents of __show_regs(), this line will continue
to be printed:
Opcode: 53 80 02 f0

It is not just the problem I encountered. When the process exits
unexpected, we all want to know what the instruction that caused the
process exception is.

Thanks,
Yunhui