This is a note to let you know that I've just added the patch titled objtool: Default ignore INT3 for unreachable to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: objtool-default-ignore-int3-for-unreachable.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Tue Jul 12 05:06:57 PM CEST 2022 From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Date: Tue, 8 Mar 2022 16:30:14 +0100 Subject: objtool: Default ignore INT3 for unreachable From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> commit 1ffbe4e935f9b7308615c75be990aec07464d1e7 upstream. Ignore all INT3 instructions for unreachable code warnings, similar to NOP. This allows using INT3 for various paddings instead of NOPs. Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220308154317.343312938@xxxxxxxxxxxxx Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- tools/objtool/check.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2965,9 +2965,8 @@ static int validate_branch(struct objtoo switch (insn->type) { case INSN_RETURN: - if (next_insn && next_insn->type == INSN_TRAP) { - next_insn->ignore = true; - } else if (sls && !insn->retpoline_safe) { + if (sls && !insn->retpoline_safe && + next_insn && next_insn->type != INSN_TRAP) { WARN_FUNC("missing int3 after ret", insn->sec, insn->offset); } @@ -3014,9 +3013,8 @@ static int validate_branch(struct objtoo break; case INSN_JUMP_DYNAMIC: - if (next_insn && next_insn->type == INSN_TRAP) { - next_insn->ignore = true; - } else if (sls && !insn->retpoline_safe) { + if (sls && !insn->retpoline_safe && + next_insn && next_insn->type != INSN_TRAP) { WARN_FUNC("missing int3 after indirect jump", insn->sec, insn->offset); } @@ -3187,7 +3185,7 @@ static bool ignore_unreachable_insn(stru int i; struct instruction *prev_insn; - if (insn->ignore || insn->type == INSN_NOP) + if (insn->ignore || insn->type == INSN_NOP || insn->type == INSN_TRAP) return true; /* Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are queue-5.15/x86-sev-avoid-using-__x86_return_thunk.patch queue-5.15/x86-ftrace-use-alternative-ret-encoding.patch queue-5.15/objtool-re-add-unwind_hint_-save_restore.patch queue-5.15/x86-bugs-add-retbleed-ibpb.patch queue-5.15/x86-bugs-enable-stibp-for-jmp2ret.patch queue-5.15/x86-retpoline-cleanup-some-ifdefery.patch queue-5.15/kvm-vmx-flatten-__vmx_vcpu_run.patch queue-5.15/x86-kvm-vmx-make-noinstr-clean.patch queue-5.15/objtool-x86-replace-alternatives-with-.retpoline_sites.patch queue-5.15/x86-retbleed-add-fine-grained-kconfig-knobs.patch queue-5.15/x86-cpu-amd-add-spectral-chicken.patch queue-5.15/kvm-vmx-fix-ibrs-handling-after-vmexit.patch queue-5.15/kvm-vmx-prevent-guest-rsb-poisoning-attacks-with-eibrs.patch queue-5.15/x86-vsyscall_emu-64-don-t-use-ret-in-vsyscall-emulation.patch queue-5.15/x86-add-magic-amd-return-thunk.patch queue-5.15/x86-bugs-keep-a-per-cpu-ia32_spec_ctrl-value.patch queue-5.15/x86-objtool-create-.return_sites.patch queue-5.15/x86-alternative-handle-jcc-__x86_indirect_thunk_-reg.patch queue-5.15/x86-kvm-fix-setcc-emulation-for-return-thunks.patch queue-5.15/x86-retpoline-swizzle-retpoline-thunk.patch queue-5.15/x86-speculation-fix-firmware-entry-spec_ctrl-handling.patch queue-5.15/x86-retpoline-remove-unused-replacement-symbols.patch queue-5.15/x86-speculation-add-spectre_v2-ibrs-option-to-support-kernel-ibrs.patch queue-5.15/x86-xen-add-untrain_ret.patch queue-5.15/bpf-x86-respect-x86_feature_retpoline.patch queue-5.15/x86-undo-return-thunk-damage.patch queue-5.15/x86-entry-avoid-very-early-ret.patch queue-5.15/x86-entry-move-push_and_clear_regs-back-into-error_entry.patch queue-5.15/x86-retpoline-create-a-retpoline-thunk-array.patch queue-5.15/x86-asm-fix-register-order.patch queue-5.15/x86-speculation-fill-rsb-on-vmexit-for-ibrs.patch queue-5.15/objtool-add-entry-unret-validation.patch queue-5.15/objtool-shrink-struct-instruction.patch queue-5.15/kvm-vmx-convert-launched-argument-to-flags.patch queue-5.15/x86-bpf-use-alternative-ret-encoding.patch queue-5.15/x86-common-stamp-out-the-stepping-madness.patch queue-5.15/x86-bugs-split-spectre_v2_select_mitigation-and-spectre_v2_user_select_mitigation.patch queue-5.15/x86-bugs-report-intel-retbleed-vulnerability.patch queue-5.15/bpf-x86-simplify-computing-label-offsets.patch queue-5.15/x86-cpufeatures-move-retpoline-flags-to-word-11.patch queue-5.15/x86-speculation-fix-spec_ctrl-write-on-smt-state-change.patch queue-5.15/x86-retpoline-use-mfunction-return.patch queue-5.15/x86-xen-rename-sys-entry-points.patch queue-5.15/x86-bugs-optimize-spec_ctrl-msr-writes.patch queue-5.15/x86-bugs-report-amd-retbleed-vulnerability.patch queue-5.15/x86-static_call-use-alternative-ret-encoding.patch queue-5.15/x86-speculation-fix-rsb-filling-with-config_retpoline-n.patch queue-5.15/x86-asm-fixup-odd-gen-for-each-reg.h-usage.patch queue-5.15/x86-alternative-add-debug-prints-to-apply_retpolines.patch queue-5.15/x86-use-return-thunk-in-asm-code.patch queue-5.15/objtool-classify-symbols.patch queue-5.15/intel_idle-disable-ibrs-during-long-idle.patch queue-5.15/x86-retpoline-move-the-retpoline-thunk-declarations-to-nospec-branch.h.patch queue-5.15/x86-alternative-implement-.retpoline_sites-support.patch queue-5.15/x86-alternative-try-inline-spectre_v2-retpoline-amd.patch queue-5.15/x86-entry-remove-skip_r11rcx.patch queue-5.15/objtool-explicitly-avoid-self-modifying-code-in-.altinstr_replacement.patch queue-5.15/x86-speculation-use-cached-host-spec_ctrl-value-for-guest-entry-exit.patch queue-5.15/x86-bugs-add-amd-retbleed-boot-parameter.patch queue-5.15/x86-entry-add-kernel-ibrs-implementation.patch queue-5.15/objtool-treat-.text.__x86.-as-noinstr.patch queue-5.15/objtool-introduce-cfi-hash.patch queue-5.15/objtool-default-ignore-int3-for-unreachable.patch queue-5.15/objtool-update-retpoline-validation.patch