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x86: Check stack overflow in detail 

Currently, only kernel stack is checked for the overflow, which
is not sufficient for systems that need a high reliability. To
enhance it, it is required to check the IRQ and exception
stacks, as well.

This patch checks all the stack types and will cause messages of
stacks in detail when free stack space drops below a certain
limit except user stack.

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/20111129060829.11076.51733.stgit@ltc219.sdl.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
This commit is contained in:
Mitsuo Hayasaka 2011-11-29 15:08:29 +09:00 committed by Ingo Molnar
parent 69682b625a
commit 37fe6a42b3
2 changed files with 28 additions and 8 deletions
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7
arch/x86/Kconfig.debug
View File

@ -63,8 +63,11 @@ config DEBUG_STACKOVERFLOW
bool "Check for stack overflows"
depends on DEBUG_KERNEL
---help---
This option will cause messages to be printed if free stack space
drops below a certain limit.
Say Y here if you want to check the overflows of kernel, IRQ
and exception stacks. This option will cause messages of the
stacks in detail when free stack space drops below a certain
limit.
If in doubt, say "N".
config X86_PTDUMP
bool "Export kernel pagetable layout to userspace via debugfs"

27
arch/x86/kernel/irq_64.c
View File

@ -36,18 +36,35 @@ EXPORT_PER_CPU_SYMBOL(irq_regs);
static inline void stack_overflow_check(struct pt_regs *regs)
{
#ifdef CONFIG_DEBUG_STACKOVERFLOW
struct orig_ist *oist;
u64 irq_stack_top, irq_stack_bottom;
u64 estack_top, estack_bottom;
u64 curbase = (u64)task_stack_page(current);
if (user_mode_vm(regs))
return;
WARN_ONCE(regs->sp >= curbase &&
if (regs->sp >= curbase &&
regs->sp <= curbase + THREAD_SIZE &&
regs->sp < curbase + sizeof(struct thread_info) +
sizeof(struct pt_regs) + 128,
regs->sp >= curbase + sizeof(struct thread_info) +
sizeof(struct pt_regs) + 128)
return;
"do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
current->comm, curbase, regs->sp);
irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack);
irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr);
if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
return;
oist = &__get_cpu_var(orig_ist);
estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ;
estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
if (regs->sp >= estack_top && regs->sp <= estack_bottom)
return;
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",
current->comm, curbase, regs->sp,
irq_stack_top, irq_stack_bottom,
estack_top, estack_bottom);
#endif
}