Messages in this thread Patch in this message |  | | Date | Thu, 23 Oct 2014 23:10:13 +0100 (BST) | From | Ben Harris <> | Subject | [PATCH] x86: Don't allow stackprotector without TSC |
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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 <bjh21@bjh21.me.uk>
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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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