From: sashiko-bot@kernel.org
To: "Nick Desaulniers" <ndesaulniers@google.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Will Deacon" <will@kernel.org>,
"Nathan Chancellor" <nathan@kernel.org>,
"Bill Wendling" <morbo@google.com>,
"Ben Cressey" <ben@cressey.dev>,
"Mark Rutland" <mark.rutland@arm.com>,
"Justin Stitt" <justinstitt@google.com>,
"Pasha Tatashin" <pasha.tatashin@soleen.com>
Cc: llvm@lists.linux.dev, stable@vger.kernel.org,
kexec@lists.infradead.org, "David Woodhouse" <dwmw@amazon.co.uk>,
linux-arm-kernel@lists.infradead.org,
"Sami Tolvanen" <samitolvanen@google.com>,
linux-kernel@vger.kernel.org, "Kees Cook" <kees@kernel.org>
Subject: Re: [PATCH] arm64: kexec: mark machine_kexec() __nocfi
Date: Thu, 24 Sep 2026 22:48:05 +0000 [thread overview]
Message-ID: <20260924224805.DC6151F00893@smtp.kernel.org> (raw)
In-Reply-To: <20260924-arm64-kexec-nocfi-v1-1-bbae2e2eadc8@cressey.dev>
> When the loaded image needs relocation, machine_kexec() makes an
> indirect call into the copy of arm64_relocate_new_kernel in the control
> page:
>
> kernel_reloc = (void *)kimage->arch.kern_reloc;
> kernel_reloc(kimage);
>
> With CONFIG_CFI=y the kCFI check on this call loads a type hash from
> kern_reloc - 4. arm64_relocate_new_kernel is SYM_CODE_START and carries
> no hash. Its copy also sits at the start of the control page, which is
> all that TTBR0 maps at this point, so the load faults and the kernel
> oopses after "Bye!" instead of entering the new kernel:
>
> Unable to handle kernel paging request at virtual address 00000000544bfffc
> Internal error: Oops: 0000000096000007 [#1] SMP
> [ ... ]
> ("x86/kexec: Mark machine_kexec() with __nocfi") did on x86.
>
> Fixes: efc2d0f20a9d ("arm64: kexec: keep MMU enabled during kexec relocation")
> Cc: stable@vger.kernel.org
> Signed-off-by: Ben Cressey <ben@cressey.dev>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260924-arm64-kexec-nocfi-v1-1-bbae2e2eadc8@cressey.dev?part=1
next prev parent reply other threads:[~2026-09-24 22:48 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-24 22:42 Ben Cressey
2026-09-24 22:48 ` sashiko-bot [this message]
2026-09-25 2:14 ` Kees Cook
2026-09-25 10:52 ` Mark Rutland
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