On Wed, Jul 13, 2022 at 05:38:47AM +0800, kernel test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.10.y > head: 53b881e19526bcc3e51d9668cab955c80dcf584c > commit: 7575d3f3bbd1c68d6833b45d1b98ed182832bd44 [7082/7120] x86: Use return-thunk in asm code > config: x86_64-rhel-8.3-syz (https://download.01.org/0day-ci/archive/20220713/202207130531.SkRjrrn8-lkp@xxxxxxxxx/config) > compiler: gcc-11 (Debian 11.3.0-3) 11.3.0 > reproduce (this is a W=1 build): > # https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=7575d3f3bbd1c68d6833b45d1b98ed182832bd44 > git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git > git fetch --no-tags linux-stable-rc linux-5.10.y > git checkout 7575d3f3bbd1c68d6833b45d1b98ed182832bd44 > # save the config file > mkdir build_dir && cp config build_dir/.config > make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/ > > If you fix the issue, kindly add following tag where applicable > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > All warnings (new ones prefixed by >>): > > >> arch/x86/kernel/head_64.o: warning: objtool: xen_hypercall_mmu_update(): can't find starting instruction > > -- > 0-DAY CI Kernel Test Service > https://01.org/lkp Please add the following patch to fix this. This would also be needed for 5.15-stable. Ben. From: Ben Hutchings <ben@xxxxxxxxxxxxxxx> Date: Thu, 14 Jul 2022 00:39:33 +0200 Subject: [PATCH] x86/xen: Fix initialisation in hypercall_page after rethunk The hypercall_page is special and the RETs there should not be changed into rethunk calls (but can have SLS mitigation). Change the initial instructions to ret + int3 padding, as was done in upstream commit 5b2fc51576ef "x86/ibt,xen: Sprinkle the ENDBR". Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- arch/x86/xen/xen-head.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S index 38b73e7e54ba..2a3ef5fcba34 100644 --- a/arch/x86/xen/xen-head.S +++ b/arch/x86/xen/xen-head.S @@ -69,9 +69,9 @@ SYM_CODE_END(asm_cpu_bringup_and_idle) SYM_CODE_START(hypercall_page) .rept (PAGE_SIZE / 32) UNWIND_HINT_FUNC - .skip 31, 0x90 ANNOTATE_UNRET_SAFE - RET + ret + .skip 31, 0xcc .endr #define HYPERCALL(n) \ -- Ben Hutchings Always try to do things in chronological order; it's less confusing that way.
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