On 2021/9/18 上午12:40, Peter Zijlstra wrote:
[snip]
> - printk(KERN_EMERG "BUG: stack guard page was hit at %p (stack is %p..%p)\n",
> - (void *)fault_address, current->stack,
> - (char *)current->stack + THREAD_SIZE - 1);
> - die(message, regs, 0);
> + const char *name = stack_type_name(info->type);
> +
> + printk(KERN_EMERG "BUG: %s stack guard page was hit at %p (stack is %p..%p)\n",
> + name, (void *)fault_address, info->begin, info->end);
Just found that the printed pointer address is not correct:
BUG: NMI stack guard page was hit at 0000000085fd977b (stack is 000000003a55b09e..00000000d8cce1a5)
Maybe we could use %px instead?
Regards,
Michael Wang
> +
> + die("stack guard page", regs, 0);
>
> /* Be absolutely certain we don't return. */
> - panic("%s", message);
> + panic("%s stack guard hit", name);
> }
> #endif
>
> @@ -353,6 +355,7 @@ DEFINE_IDTENTRY_DF(exc_double_fault)
>
> #ifdef CONFIG_VMAP_STACK
> unsigned long address = read_cr2();
> + struct stack_info info;
> #endif
>
> #ifdef CONFIG_X86_ESPFIX64
> @@ -455,10 +458,8 @@ DEFINE_IDTENTRY_DF(exc_double_fault)
> * stack even if the actual trigger for the double fault was
> * something else.
> */
> - if ((unsigned long)task_stack_page(tsk) - 1 - address < PAGE_SIZE) {
> - handle_stack_overflow("kernel stack overflow (double-fault)",
> - regs, address);
> - }
> + if (get_stack_guard_info((void *)address, &info))
> + handle_stack_overflow(regs, address, &info);
> #endif
>
> pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> index b2eefdefc108..edb5152f0866 100644
> --- a/arch/x86/mm/fault.c
> +++ b/arch/x86/mm/fault.c
> @@ -32,6 +32,7 @@
> #include <asm/pgtable_areas.h> /* VMALLOC_START, ... */
> #include <asm/kvm_para.h> /* kvm_handle_async_pf */
> #include <asm/vdso.h> /* fixup_vdso_exception() */
> +#include <asm/irq_stack.h>
>
> #define CREATE_TRACE_POINTS
> #include <asm/trace/exceptions.h>
> @@ -631,6 +632,9 @@ static noinline void
> page_fault_oops(struct pt_regs *regs, unsigned long error_code,
> unsigned long address)
> {
> +#ifdef CONFIG_VMAP_STACK
> + struct stack_info info;
> +#endif
> unsigned long flags;
> int sig;
>
> @@ -649,9 +653,7 @@ page_fault_oops(struct pt_regs *regs, unsigned long error_code,
> * that we're in vmalloc space to avoid this.
> */
> if (is_vmalloc_addr((void *)address) &&
> - (((unsigned long)current->stack - 1 - address < PAGE_SIZE) ||
> - address - ((unsigned long)current->stack + THREAD_SIZE) < PAGE_SIZE)) {
> - unsigned long stack = __this_cpu_ist_top_va(DF) - sizeof(void *);
> + get_stack_guard_info((void *)address, &info)) {
> /*
> * We're likely to be running with very little stack space
> * left. It's plausible that we'd hit this condition but
> @@ -662,13 +664,11 @@ page_fault_oops(struct pt_regs *regs, unsigned long error_code,
> * and then double-fault, though, because we're likely to
> * break the console driver and lose most of the stack dump.
> */
> - asm volatile ("movq %[stack], %%rsp\n\t"
> - "call handle_stack_overflow\n\t"
> - "1: jmp 1b"
> - : ASM_CALL_CONSTRAINT
> - : "D" ("kernel stack overflow (page fault)"),
> - "S" (regs), "d" (address),
> - [stack] "rm" (stack));
> + call_on_stack(__this_cpu_ist_top_va(DF) - sizeof(void*),
> + handle_stack_overflow,
> + ASM_CALL_ARG3,
> + , [arg1] "r" (regs), [arg2] "r" (address), [arg3] "r" (&info));
> +
> unreachable();
> }
> #endif
>
