Patch "x86/debug, objtool: Annotate WARN()-related UD2 as reachable" has been added to the 4.15-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    x86/debug, objtool: Annotate WARN()-related UD2 as reachable

to the 4.15-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:
     x86-debug-objtool-annotate-warn-related-ud2-as-reachable.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 2b5db66862b95532cb6cca8165ae6eb73633cf85 Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe@redhat.com>
Date: Thu, 8 Feb 2018 17:09:26 -0600
Subject: x86/debug, objtool: Annotate WARN()-related UD2 as reachable

From: Josh Poimboeuf <jpoimboe@redhat.com>

commit 2b5db66862b95532cb6cca8165ae6eb73633cf85 upstream.

By default, objtool assumes that a UD2 is a dead end.  This is mainly
because GCC 7+ sometimes inserts a UD2 when it detects a divide-by-zero
condition.

Now that WARN() is moving back to UD2, annotate the code after it as
reachable so objtool can follow the code flow.

Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kbuild test robot <fengguang.wu@intel.com>
Link: http://lkml.kernel.org/r/0e483379275a42626ba8898117f918e1bf661e40.1518130694.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/include/asm/bug.h |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -77,7 +77,11 @@ do {								\
 	unreachable();						\
 } while (0)
 
-#define __WARN_FLAGS(flags)	_BUG_FLAGS(ASM_UD0, BUGFLAG_WARNING|(flags))
+#define __WARN_FLAGS(flags)					\
+do {								\
+	_BUG_FLAGS(ASM_UD0, BUGFLAG_WARNING|(flags));		\
+	annotate_reachable();					\
+} while (0)
 
 #include <asm-generic/bug.h>
 


Patches currently in stable-queue which might be from jpoimboe@redhat.com are

queue-4.15/x86-entry-64-interleave-xor-register-clearing-with-push-instructions.patch
queue-4.15/x86-entry-64-merge-the-pop_c_regs-and-pop_extra_regs-macros-into-a-single-pop_regs-macro.patch
queue-4.15/x86-entry-64-remove-the-unused-icebp-macro.patch
queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch
queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch
queue-4.15/x86-speculation-add-asm-msr-index.h-dependency.patch
queue-4.15/x86-entry-64-use-push_and_clean_regs-in-more-cases.patch
queue-4.15/x86-debug-use-ud2-for-warn.patch
queue-4.15/x86-entry-64-fix-paranoid_entry-frame-pointer-warning.patch
queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch
queue-4.15/x86-entry-64-clear-registers-for-exceptions-interrupts-to-reduce-speculation-attack-surface.patch
queue-4.15/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch
queue-4.15/x86-entry-64-merge-save_c_regs-and-save_extra_regs-remove-unused-extensions.patch
queue-4.15/x86-debug-objtool-annotate-warn-related-ud2-as-reachable.patch
queue-4.15/objtool-fix-segfault-in-ignore_unreachable_insn.patch
queue-4.15/x86-entry-64-indent-push_and_clear_regs-and-pop_regs-properly.patch
queue-4.15/x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch
queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch
queue-4.15/x86-mm-pti-fix-pti-comment-in-entry_syscall_64.patch
queue-4.15/x86-entry-64-get-rid-of-the-alloc_pt_gpregs_on_stack-and-save_and_clear_regs-macros.patch
queue-4.15/x86-speculation-clean-up-various-spectre-related-details.patch
queue-4.15/x86-entry-64-introduce-the-push_and_clean_regs-macro.patch
queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch
queue-4.15/x86-entry-64-compat-clear-registers-for-compat-syscalls-to-reduce-speculation-attack-surface.patch
queue-4.15/x86-mm-rename-flush_tlb_single-and-flush_tlb_one-to-__flush_tlb_one_.patch
queue-4.15/x86-entry-64-fix-cr3-restore-in-paranoid_exit.patch