On x86, boot_init_stack_canary() unconditionally calls
__native_read_tsc(). This means that when a kernel with
CONFIG_CC_STACKPROTECTOR enabled is booted on a CPU without a TSC, the
kernel hangs at startup. See <https://bugs.debian.org/766105> for an
example.
To avoid this, make HAVE_CC_STACKPROTECTOR dependent on X86_TSC, which is
defined iff all supported processors have a TSC. Setting the minimum
processor type to one without TSC thus disables the stack protector,
making the kernel bootable on such processors.
Signed-off-by: Ben Harris <bj...@bjh21.me.uk>
---
This patch is against v3.18-rc1.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f2327e8..5acee0f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -129,7 +129,6 @@ config X86
select RTC_LIB
select HAVE_DEBUG_STACKOVERFLOW
select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
- select HAVE_CC_STACKPROTECTOR
select GENERIC_CPU_AUTOPROBE
select HAVE_ARCH_AUDITSYSCALL
select ARCH_SUPPORTS_ATOMIC_RMW
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 6983314..9626e47 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -360,6 +360,7 @@ config X86_P6_NOP
config X86_TSC
def_bool y
depends on (MWINCHIP3D || MCRUSOE || MEFFICEON || MCYRIXIII || MK7 ||
MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || M586MMX
|| M586TSC || MK8 || MVIAC3_2 || MVIAC7 || MGEODEGX1 || MGEODE_LX || MCORE2 ||
MATOM) || X86_64
+ select HAVE_CC_STACKPROTECTOR
config X86_CMPXCHG64
def_bool y
--
Ben Harris
--
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