Re: [PATCH] riscv: Fix a NULL pointer reference in machine_kexec_prepare

From: Baoquan He <baoquan.he@linux.dev>
To: Tao Liu <ltao@redhat.com>
Cc: Baoquan He <bhe@redhat.com>,
	kexec@lists.infradead.org, pjw@kernel.org, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, alex@ghiti.fr,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: Fix a NULL pointer reference in machine_kexec_prepare
Date: Mon, 29 Jun 2026 10:44:54 +0800	[thread overview]
Message-ID: <akHcJpVXP2tyi9XS@MiWiFi-R3L-srv> (raw)
In-Reply-To: <CAO7dBbVfMtHDocudv2LgoJR1dNy8CufjB8SEz=BZ+hK6Ycu6Yw@mail.gmail.com>

On 06/28/26 at 10:38am, Tao Liu wrote:
......
> > >                /*
> > >                 * Some segments (e.g. IMA) reserve space but have no buffer
> > >                 * loaded yet. Skip them as they cannot contain an FDT.
> > >                 */
> > > And is there any other place where the similar issue exists? e.g on LoongArch?
> 
> I have tested in LoongArch, it doesn't have the similar issue. The
> reason is, in arch/loongarch/kernel/machine_kexec.c:machine_kexec_prepare(),
> the unchecked memcpy() only happens for none kexec file load, however
> ima_add_kexec_buffer() requires kexec file load. So the condition
> isn't met.

OK, that's good, thanks for the effort.

> 
> > >
> > > Other than above concerns, this patch looks good to me:
> > >
> > > Acked-by: Baoquan He <bhe@redhat.com>
> 
> Thanks for your code review and suggestions!
> 
> Thanks,
> Tao Liu
> 
> > >
> > > > >                 if (image->file_mode)
> > > > >                         memcpy(&fdt, image->segment[i].buf, sizeof(fdt));
> > > > >                 else if (copy_from_user(&fdt, image->segment[i].buf, sizeof(fdt)))
> > > > > --
> > > > > 2.47.0
> > > > >
> > > >
> > > >
> > > > _______________________________________________
> > > > linux-riscv mailing list
> > > > linux-riscv@lists.infradead.org
> > > > http://lists.infradead.org/mailman/listinfo/linux-riscv
> > > >
> > >
> 