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467e6b7a7c
The overflow checking of kernel stack checks if the stack pointer points to the available kernel stack range, which is derived from the original overflow checking. It is clear that curbase address is always less than low boundary of available kernel stack. So, this patch removes the first condition that checks if the pointer is higher than curbase. Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Randy Dunlap <rdunlap@xenotime.net> Link: http://lkml.kernel.org/r/20111129060845.11076.40916.stgit@ltc219.sdl.hitachi.co.jp Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com>
108 lines
2.7 KiB
C
108 lines
2.7 KiB
C
/*
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* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
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*
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* This file contains the lowest level x86_64-specific interrupt
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* entry and irq statistics code. All the remaining irq logic is
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* done by the generic kernel/irq/ code and in the
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* x86_64-specific irq controller code. (e.g. i8259.c and
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* io_apic.c.)
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*/
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#include <linux/kernel_stat.h>
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#include <linux/interrupt.h>
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#include <linux/seq_file.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/ftrace.h>
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#include <linux/uaccess.h>
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#include <linux/smp.h>
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#include <asm/io_apic.h>
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#include <asm/idle.h>
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#include <asm/apic.h>
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DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
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EXPORT_PER_CPU_SYMBOL(irq_stat);
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DEFINE_PER_CPU(struct pt_regs *, irq_regs);
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EXPORT_PER_CPU_SYMBOL(irq_regs);
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int sysctl_panic_on_stackoverflow;
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/*
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* Probabilistic stack overflow check:
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*
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* Only check the stack in process context, because everything else
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* runs on the big interrupt stacks. Checking reliably is too expensive,
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* so we just check from interrupts.
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*/
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static inline void stack_overflow_check(struct pt_regs *regs)
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{
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#ifdef CONFIG_DEBUG_STACKOVERFLOW
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struct orig_ist *oist;
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u64 irq_stack_top, irq_stack_bottom;
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u64 estack_top, estack_bottom;
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u64 curbase = (u64)task_stack_page(current);
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if (user_mode_vm(regs))
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return;
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if (regs->sp >= curbase + sizeof(struct thread_info) +
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sizeof(struct pt_regs) + 128 &&
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regs->sp <= curbase + THREAD_SIZE)
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return;
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irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack);
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irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr);
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if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
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return;
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oist = &__get_cpu_var(orig_ist);
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estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ;
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estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
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if (regs->sp >= estack_top && regs->sp <= estack_bottom)
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return;
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WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx)\n",
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current->comm, curbase, regs->sp,
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irq_stack_top, irq_stack_bottom,
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estack_top, estack_bottom);
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if (sysctl_panic_on_stackoverflow)
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panic("low stack detected by irq handler - check messages\n");
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#endif
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}
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bool handle_irq(unsigned irq, struct pt_regs *regs)
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{
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struct irq_desc *desc;
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stack_overflow_check(regs);
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desc = irq_to_desc(irq);
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if (unlikely(!desc))
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return false;
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generic_handle_irq_desc(irq, desc);
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return true;
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}
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extern void call_softirq(void);
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asmlinkage void do_softirq(void)
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{
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__u32 pending;
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unsigned long flags;
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if (in_interrupt())
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return;
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local_irq_save(flags);
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pending = local_softirq_pending();
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/* Switch to interrupt stack */
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if (pending) {
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call_softirq();
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WARN_ON_ONCE(softirq_count());
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}
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local_irq_restore(flags);
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}
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