Commit-ID: 117ed45485413b1977bfc638c32bf5b01d53c62b Gitweb: https://git.kernel.org/tip/117ed45485413b1977bfc638c32bf5b01d53c62b Author: Thomas Gleixner <[email protected]> AuthorDate: Sun, 14 Apr 2019 18:00:08 +0200 Committer: Borislav Petkov <[email protected]> CommitDate: Wed, 17 Apr 2019 15:41:48 +0200
x86/irq/64: Remove stack overflow debug code All stack types on x86 64-bit have guard pages now. So there is no point in executing probabilistic overflow checks as the guard pages are a accurate and reliable overflow prevention. Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Nicolai Stange <[email protected]> Cc: Sean Christopherson <[email protected]> Cc: x86-ml <[email protected]> Link: https://lkml.kernel.org/r/[email protected] --- arch/x86/Kconfig | 2 +- arch/x86/kernel/irq_64.c | 56 ------------------------------------------------ 2 files changed, 1 insertion(+), 57 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 5ad92419be19..fd06614b09a7 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -14,6 +14,7 @@ config X86_32 select ARCH_WANT_IPC_PARSE_VERSION select CLKSRC_I8253 select CLONE_BACKWARDS + select HAVE_DEBUG_STACKOVERFLOW select MODULES_USE_ELF_REL select OLD_SIGACTION @@ -138,7 +139,6 @@ config X86 select HAVE_COPY_THREAD_TLS select HAVE_C_RECORDMCOUNT select HAVE_DEBUG_KMEMLEAK - select HAVE_DEBUG_STACKOVERFLOW select HAVE_DMA_CONTIGUOUS select HAVE_DYNAMIC_FTRACE select HAVE_DYNAMIC_FTRACE_WITH_REGS diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c index f107eb2021f6..6bf6517a05bb 100644 --- a/arch/x86/kernel/irq_64.c +++ b/arch/x86/kernel/irq_64.c @@ -26,64 +26,8 @@ DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible; DECLARE_INIT_PER_CPU(irq_stack_backing_store); -int sysctl_panic_on_stackoverflow; - -/* - * Probabilistic stack overflow check: - * - * Regular device interrupts can enter on the following stacks: - * - * - User stack - * - * - Kernel task stack - * - * - Interrupt stack if a device driver reenables interrupts - * which should only happen in really old drivers. - * - * - Debug IST stack - * - * All other contexts are invalid. - */ -static inline void stack_overflow_check(struct pt_regs *regs) -{ -#ifdef CONFIG_DEBUG_STACKOVERFLOW -#define STACK_MARGIN 128 - u64 irq_stack_top, irq_stack_bottom, estack_top, estack_bottom; - u64 curbase = (u64)task_stack_page(current); - struct cea_exception_stacks *estacks; - - if (user_mode(regs)) - return; - - if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_MARGIN && - regs->sp <= curbase + THREAD_SIZE) - return; - - irq_stack_top = (u64)__this_cpu_read(hardirq_stack_ptr); - irq_stack_bottom = irq_stack_top - IRQ_STACK_SIZE + STACK_MARGIN; - if (regs->sp >= irq_stack_bottom && regs->sp <= irq_stack_top) - return; - - estacks = __this_cpu_read(cea_exception_stacks); - estack_top = CEA_ESTACK_TOP(estacks, DB); - estack_bottom = CEA_ESTACK_BOT(estacks, DB) + STACK_MARGIN; - if (regs->sp >= estack_bottom && regs->sp <= estack_top) - return; - - WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx, irq stack:%Lx-%Lx, exception stack: %Lx-%Lx, ip:%pF)\n", - current->comm, curbase, regs->sp, - irq_stack_bottom, irq_stack_top, - estack_bottom, estack_top, (void *)regs->ip); - - if (sysctl_panic_on_stackoverflow) - panic("low stack detected by irq handler - check messages\n"); -#endif -} - bool handle_irq(struct irq_desc *desc, struct pt_regs *regs) { - stack_overflow_check(regs); - if (IS_ERR_OR_NULL(desc)) return false;
