171 lines
6 KiB
Diff
171 lines
6 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Josh Poimboeuf <jpoimboe@redhat.com>
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Date: Tue, 25 Jul 2017 08:54:24 -0500
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Subject: [PATCH] x86/kconfig: Consolidate unwinders into multiple choice
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selection
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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CVE-2017-5754
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There are three mutually exclusive unwinders. Make that more obvious by
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combining them into a multiple-choice selection:
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CONFIG_FRAME_POINTER_UNWINDER
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CONFIG_ORC_UNWINDER
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CONFIG_GUESS_UNWINDER (if CONFIG_EXPERT=y)
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Frame pointers are still the default (for now).
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The old CONFIG_FRAME_POINTER option is still used in some
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arch-independent places, so keep it around, but make it
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invisible to the user on x86 - it's now selected by
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CONFIG_FRAME_POINTER_UNWINDER=y.
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Suggested-by: Ingo Molnar <mingo@kernel.org>
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Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
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Cc: Andy Lutomirski <luto@kernel.org>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Brian Gerst <brgerst@gmail.com>
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Cc: Denys Vlasenko <dvlasenk@redhat.com>
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Cc: H. Peter Anvin <hpa@zytor.com>
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Cc: Jiri Slaby <jslaby@suse.cz>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Mike Galbraith <efault@gmx.de>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Thomas Gleixner <tglx@linutronix.de>
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Cc: live-patching@vger.kernel.org
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Link: http://lkml.kernel.org/r/20170725135424.zukjmgpz3plf5pmt@treble
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit 81d387190039c14edac8de2b3ec789beb899afd9)
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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(cherry picked from commit 26ddacc1e6333555e4a6bd63c4c935b323509f92)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/include/asm/unwind.h | 4 ++--
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arch/x86/Kconfig | 3 +--
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arch/x86/Kconfig.debug | 45 +++++++++++++++++++++++++++++++++++++------
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arch/x86/configs/tiny.config | 2 ++
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4 files changed, 44 insertions(+), 10 deletions(-)
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diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h
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index 25b8d31a007d..e9f793e2df7a 100644
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--- a/arch/x86/include/asm/unwind.h
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+++ b/arch/x86/include/asm/unwind.h
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@@ -16,7 +16,7 @@ struct unwind_state {
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bool signal, full_regs;
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unsigned long sp, bp, ip;
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struct pt_regs *regs;
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-#elif defined(CONFIG_FRAME_POINTER)
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+#elif defined(CONFIG_FRAME_POINTER_UNWINDER)
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bool got_irq;
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unsigned long *bp, *orig_sp, ip;
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struct pt_regs *regs;
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@@ -50,7 +50,7 @@ void unwind_start(struct unwind_state *state, struct task_struct *task,
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__unwind_start(state, task, regs, first_frame);
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}
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-#if defined(CONFIG_ORC_UNWINDER) || defined(CONFIG_FRAME_POINTER)
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+#if defined(CONFIG_ORC_UNWINDER) || defined(CONFIG_FRAME_POINTER_UNWINDER)
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static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
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{
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if (unwind_done(state))
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diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
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index d6f45f6d1054..3a0b8cb57caf 100644
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--- a/arch/x86/Kconfig
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+++ b/arch/x86/Kconfig
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@@ -73,7 +73,6 @@ config X86
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select ARCH_USE_QUEUED_RWLOCKS
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select ARCH_USE_QUEUED_SPINLOCKS
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select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
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- select ARCH_WANT_FRAME_POINTERS
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select ARCH_WANTS_DYNAMIC_TASK_STRUCT
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select ARCH_WANTS_THP_SWAP if X86_64
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select BUILDTIME_EXTABLE_SORT
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@@ -169,7 +168,7 @@ config X86
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select HAVE_PERF_REGS
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select HAVE_PERF_USER_STACK_DUMP
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select HAVE_REGS_AND_STACK_ACCESS_API
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- select HAVE_RELIABLE_STACKTRACE if X86_64 && FRAME_POINTER && STACK_VALIDATION
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+ select HAVE_RELIABLE_STACKTRACE if X86_64 && FRAME_POINTER_UNWINDER && STACK_VALIDATION
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select HAVE_STACK_VALIDATION if X86_64
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select HAVE_SYSCALL_TRACEPOINTS
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select HAVE_UNSTABLE_SCHED_CLOCK
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diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
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index d5bca2ec8a74..c441b5d65ec8 100644
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--- a/arch/x86/Kconfig.debug
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+++ b/arch/x86/Kconfig.debug
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@@ -356,6 +356,29 @@ config PUNIT_ATOM_DEBUG
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The current power state can be read from
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/sys/kernel/debug/punit_atom/dev_power_state
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+choice
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+ prompt "Choose kernel unwinder"
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+ default FRAME_POINTER_UNWINDER
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+ ---help---
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+ This determines which method will be used for unwinding kernel stack
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+ traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack,
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+ livepatch, lockdep, and more.
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+
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+config FRAME_POINTER_UNWINDER
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+ bool "Frame pointer unwinder"
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+ select FRAME_POINTER
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+ ---help---
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+ This option enables the frame pointer unwinder for unwinding kernel
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+ stack traces.
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+
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+ The unwinder itself is fast and it uses less RAM than the ORC
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+ unwinder, but the kernel text size will grow by ~3% and the kernel's
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+ overall performance will degrade by roughly 5-10%.
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+
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+ This option is recommended if you want to use the livepatch
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+ consistency model, as this is currently the only way to get a
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+ reliable stack trace (CONFIG_HAVE_RELIABLE_STACKTRACE).
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+
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config ORC_UNWINDER
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bool "ORC unwinder"
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depends on X86_64
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@@ -373,12 +396,22 @@ config ORC_UNWINDER
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Enabling this option will increase the kernel's runtime memory usage
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by roughly 2-4MB, depending on your kernel config.
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-config FRAME_POINTER_UNWINDER
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- def_bool y
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- depends on !ORC_UNWINDER && FRAME_POINTER
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-
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config GUESS_UNWINDER
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- def_bool y
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- depends on !ORC_UNWINDER && !FRAME_POINTER
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+ bool "Guess unwinder"
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+ depends on EXPERT
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+ ---help---
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+ This option enables the "guess" unwinder for unwinding kernel stack
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+ traces. It scans the stack and reports every kernel text address it
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+ finds. Some of the addresses it reports may be incorrect.
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+
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+ While this option often produces false positives, it can still be
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+ useful in many cases. Unlike the other unwinders, it has no runtime
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+ overhead.
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+
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+endchoice
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+
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+config FRAME_POINTER
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+ depends on !ORC_UNWINDER && !GUESS_UNWINDER
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+ bool
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endmenu
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diff --git a/arch/x86/configs/tiny.config b/arch/x86/configs/tiny.config
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index 4b429df40d7a..550cd5012b73 100644
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--- a/arch/x86/configs/tiny.config
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+++ b/arch/x86/configs/tiny.config
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@@ -1,3 +1,5 @@
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CONFIG_NOHIGHMEM=y
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# CONFIG_HIGHMEM4G is not set
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# CONFIG_HIGHMEM64G is not set
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+CONFIG_GUESS_UNWINDER=y
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+# CONFIG_FRAME_POINTER_UNWINDER is not set
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--
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2.14.2
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