On Mon, Nov 07, 2011 at 02:53:08PM +0900, Mitsuo Hayasaka wrote:
> Currently, messages are just output on the detection of stack overflow,
> which is not sufficient for enterprise systems since it may corrupt data.
> To enhance reliability, it is required to stop the systems.
Why not just make the stack_overflow_check() return a value that it should
not handle the IRQ and perhaps silence (disable_chip) the IRQ line?
That will still let the system run, albeit .. without certain parts
not working right.. So perhaps re-enable the chip later on?
Or is there really no way to recover from this?
>
> This patch causes a panic according to a sysctl parameter
> panic_on_stackoverflow when detecting it. It is disabled by default.
>
> Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@xxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> ---
>
> arch/x86/kernel/irq_32.c | 2 ++
> arch/x86/kernel/irq_64.c | 16 +++++++++++-----
> 2 files changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
> index 7209070..e16e99eb 100644
> --- a/arch/x86/kernel/irq_32.c
> +++ b/arch/x86/kernel/irq_32.c
> @@ -43,6 +43,8 @@ static void print_stack_overflow(void)
> {
> printk(KERN_WARNING "low stack detected by irq handler\n");
> dump_stack();
> + if (sysctl_panic_on_stackoverflow)
> + panic("low stack detected by irq handler - check messages\n");
> }
>
> #else
> diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
> index d720813..f7baedd 100644
> --- a/arch/x86/kernel/irq_64.c
> +++ b/arch/x86/kernel/irq_64.c
> @@ -69,14 +69,20 @@ static inline void stack_overflow_check(struct pt_regs *regs)
> current->comm, curbase, regs->sp,
> irq_stack_top, irq_stack_bottom,
> estack_top, estack_bottom);
> + if (sysctl_panic_on_stackoverflow)
> + panic("low stack detected by irq handler - check messages\n");
> #else
> - WARN_ONCE(regs->sp >= curbase &&
> - regs->sp <= curbase + THREAD_SIZE &&
> - regs->sp < curbase + sizeof(struct thread_info) +
> - sizeof(struct pt_regs) + 128,
> -
> + if (regs->sp >= curbase &&
> + regs->sp <= curbase + THREAD_SIZE &&
> + regs->sp < curbase + sizeof(struct thread_info) +
> + sizeof(struct pt_regs) + 128) {
> + WARN_ONCE(1,
> "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
> current->comm, curbase, regs->sp);
> + if (sysctl_panic_on_stackoverflow)
> + panic("low stack detected by irq handler - check messages\n");
> + }
> +
> #endif /* CONFIG_DEBUG_STACKOVERFLOW_DETAIL */
> #endif
> }
>
> --
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