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From:   Guo Ren <guoren@kernel.org>
Date:   Mon, 6 Feb 2023 11:10:12 +0800
Message-ID: <CAJF2gTTuva2HmoJymP1atfKxudS67XY8pygukgEH98D=o3dwUw@mail.gmail.com>
Subject: Re: [PATCH] riscv: kprobe: Fixup misaligned load text
To:     =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>
Cc:     Jessica Clarke <jrtc27@jrtc27.com>,
        Palmer Dabbelt <palmer@rivosinc.com>,
        Conor Dooley <conor.dooley@microchip.com>,
        liaochang1@huawei.com, linux-arch <linux-arch@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        Guo Ren <guoren@linux.alibaba.com>,
        Bjorn Topel <bjorn.topel@gmail.com>
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On Thu, Feb 2, 2023 at 10:36 PM Bj=C3=B6rn T=C3=B6pel <bjorn@kernel.org> wr=
ote:
>
> Jessica Clarke <jrtc27@jrtc27.com> writes:
>
> >> +    p->opcode =3D *insn++;
> >> +    if (GET_INSN_LENGTH(p->opcode) =3D=3D 4)
> >> +            p->opcode |=3D *insn << 16;
> >
> > *insn gets promoted to int not unsigned so this is UB if bit 15 is set.
>
> Ugh. Good catch! I guess we can't get rid of *that* explicit cast to
> kprobe_opcode_t here...
Hi Bjorn & Jessica,
Thx for reviewing.

The new version came out:
https://lore.kernel.org/linux-riscv/20230204063531.740220-1-guoren@kernel.o=
rg/


--
Best Regards
 Guo Ren