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

x86/unwind: Make CONFIG_UNWINDER_ORC=y the default in kconfig for 64-bit

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: x86-unwind-make-config_unwinder_orc-y-the-default-in-kconfig-for-64-bit.patch and it can be found in the queue-4.14 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 fc72ae40e30327aa24eb88a24b9c7058f938bd36 Mon Sep 17 00:00:00 2001

From: Josh Poimboeuf jpoimboe@redhat.com Date: Fri, 13 Oct 2017 15:02:01 -0500 Subject: x86/unwind: Make CONFIG_UNWINDER_ORC=y the default in kconfig for 64-bit

From: Josh Poimboeuf jpoimboe@redhat.com

commit fc72ae40e30327aa24eb88a24b9c7058f938bd36 upstream.

The ORC unwinder has been stable in testing so far. Give it much wider testing by making it the default in kconfig for x86_64. It's not yet supported for 32-bit, so leave frame pointers as the default there.

Suggested-by: Ingo Molnar mingo@kernel.org Signed-off-by: Josh Poimboeuf jpoimboe@redhat.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/9b1237bbe7244ed9cdf8db2dcb1253e37e1c341e.1507924831... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/x86/Kconfig.debug | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-)

--- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -359,27 +359,13 @@ config PUNIT_ATOM_DEBUG

choice prompt "Choose kernel unwinder" - default UNWINDER_FRAME_POINTER + default UNWINDER_ORC if X86_64 + default UNWINDER_FRAME_POINTER if X86_32 ---help--- This determines which method will be used for unwinding kernel stack traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack, livepatch, lockdep, and more.

-config UNWINDER_FRAME_POINTER - bool "Frame pointer unwinder" - select FRAME_POINTER - ---help--- - This option enables the frame pointer unwinder for unwinding kernel - stack traces. - - The unwinder itself is fast and it uses less RAM than the ORC - unwinder, but the kernel text size will grow by ~3% and the kernel's - overall performance will degrade by roughly 5-10%. - - This option is recommended if you want to use the livepatch - consistency model, as this is currently the only way to get a - reliable stack trace (CONFIG_HAVE_RELIABLE_STACKTRACE). - config UNWINDER_ORC bool "ORC unwinder" depends on X86_64 @@ -396,6 +382,21 @@ config UNWINDER_ORC Enabling this option will increase the kernel's runtime memory usage by roughly 2-4MB, depending on your kernel config.

+config UNWINDER_FRAME_POINTER + bool "Frame pointer unwinder" + select FRAME_POINTER + ---help--- + This option enables the frame pointer unwinder for unwinding kernel + stack traces. + + The unwinder itself is fast and it uses less RAM than the ORC + unwinder, but the kernel text size will grow by ~3% and the kernel's + overall performance will degrade by roughly 5-10%. + + This option is recommended if you want to use the livepatch + consistency model, as this is currently the only way to get a + reliable stack trace (CONFIG_HAVE_RELIABLE_STACKTRACE). + config UNWINDER_GUESS bool "Guess unwinder" depends on EXPERT

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

queue-4.14/x86-asm-don-t-use-the-confusing-.ifeq-directive.patch queue-4.14/x86-boot-relocate-definition-of-the-initial-state-of-cr0.patch queue-4.14/objtool-don-t-report-end-of-section-error-after-an-empty-unwind-hint.patch queue-4.14/x86-xen-fix-xen-head-elf-annotations.patch queue-4.14/x86-head-fix-head-elf-function-annotations.patch queue-4.14/objtool-print-top-level-commands-on-incorrect-usage.patch queue-4.14/x86-unwind-rename-unwinder-config-options-to-config_unwinder_.patch queue-4.14/x86-head-add-unwind-hint-annotations.patch queue-4.14/x86-head-remove-unused-bad_address-code.patch queue-4.14/x86-xen-add-unwind-hint-annotations.patch queue-4.14/x86-head-remove-confusing-comment.patch queue-4.14/x86-unwinder-make-config_unwinder_orc-y-the-default-in-the-64-bit-defconfig.patch queue-4.14/x86-unwind-make-config_unwinder_orc-y-the-default-in-kconfig-for-64-bit.patch queue-4.14/x86-mm-relocate-page-fault-error-codes-to-traps.h.patch queue-4.14/x86-boot-annotate-verify_cpu-as-a-callable-function.patch