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@i...) 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/c... 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@intel.com
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@decadent.org.uk 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@decadent.org.uk --- 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) \