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Peter Anvin" , David Woodhouse , "Kirill A. Shutemov" , Kai Huang , Nikolay Borisov , linux-kernel@vger.kernel.org, Simon Horman , Dave Young , Peter Zijlstra , jpoimboe@kernel.org, bsz@amazon.de References: <20241205153343.3275139-1-dwmw2@infradead.org> <20241205153343.3275139-14-dwmw2@infradead.org> Content-Language: en-US From: "Ning, Hongyu" In-Reply-To: <20241205153343.3275139-14-dwmw2@infradead.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024/12/5 23:05, David Woodhouse wrote: > From: David Woodhouse > > All writes to the page now happen before it gets marked as executable > (or after it's already switched to the identmap page tables where it's > OK to be RWX). > > Signed-off-by: David Woodhouse > --- > arch/x86/kernel/machine_kexec_64.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c > index c9fd60f8f806..9232ad1562c8 100644 > --- a/arch/x86/kernel/machine_kexec_64.c > +++ b/arch/x86/kernel/machine_kexec_64.c > @@ -323,7 +323,7 @@ int machine_kexec_prepare(struct kimage *image) > > __memcpy(control_page, __relocate_kernel_start, reloc_end - reloc_start); > > - set_memory_x((unsigned long)control_page, 1); > + set_memory_rox((unsigned long)control_page, 1); > > return 0; > } > @@ -333,6 +333,7 @@ void machine_kexec_cleanup(struct kimage *image) > void *control_page = page_address(image->control_code_page); > > set_memory_nx((unsigned long)control_page, 1); > + set_memory_rw((unsigned long)control_page, 1); > > free_transition_pgtable(image); > } Hi David, I've hit some kdump/kexec regression issue for guest kernel in KVM/QEMU based VM and reported in https://bugzilla.kernel.org/show_bug.cgi?id=219592. based on further git bisect, it seems to be related with this commit, would you help to take a look?