Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "Various fixes:

   - Fix the PAT performance regression that downgraded write-combining
     device memory regions to uncached.

   - There's been a number of bugs in 32-bit double fault handling -
     hopefully all fixed now.

   - Fix an LDT crash

   - Fix an FPU over-optimization that broke with GCC9 code
     optimizations.

   - Misc cleanups"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm/pat: Fix off-by-one bugs in interval tree search
  x86/ioperm: Save an indentation level in tss_update_io_bitmap()
  x86/fpu: Don't cache access to fpu_fpregs_owner_ctx
  x86/entry/32: Remove unused 'restore_all_notrace' local label
  x86/ptrace: Document FSBASE and GSBASE ABI oddities
  x86/ptrace: Remove set_segment_reg() implementations for current
  x86/traps: die() instead of panicking on a double fault
  x86/doublefault/32: Rewrite the x86_32 #DF handler and unify with 64-bit
  x86/doublefault/32: Move #DF stack and TSS to cpu_entry_area
  x86/doublefault/32: Rename doublefault.c to doublefault_32.c
  x86/traps: Disentangle the 32-bit and 64-bit doublefault code
  lkdtm: Add a DOUBLE_FAULT crash type on x86
  selftests/x86/single_step_syscall: Check SYSENTER directly
  x86/mm/32: Sync only to VMALLOC_END in vmalloc_sync_all()

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 64a59d726639..8e3a8fedfa4d 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -29,6 +29,9 @@ const char *stack_type_name(enum stack_type type)
 	if (type == STACK_TYPE_ENTRY)
 		return "ENTRY_TRAMPOLINE";
 
+	if (type == STACK_TYPE_EXCEPTION)
+		return "#DF";
+
 	return NULL;
 }
 
@@ -82,6 +85,30 @@ static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
 	return true;
 }
 
+static bool in_doublefault_stack(unsigned long *stack, struct stack_info *info)
+{
+#ifdef CONFIG_DOUBLEFAULT
+	struct cpu_entry_area *cea = get_cpu_entry_area(raw_smp_processor_id());
+	struct doublefault_stack *ss = &cea->doublefault_stack;
+
+	void *begin = ss->stack;
+	void *end = begin + sizeof(ss->stack);
+
+	if ((void *)stack < begin || (void *)stack >= end)
+		return false;
+
+	info->type	= STACK_TYPE_EXCEPTION;
+	info->begin	= begin;
+	info->end	= end;
+	info->next_sp	= (unsigned long *)this_cpu_read(cpu_tss_rw.x86_tss.sp);
+
+	return true;
+#else
+	return false;
+#endif
+}
+
+
 int get_stack_info(unsigned long *stack, struct task_struct *task,
 		   struct stack_info *info, unsigned long *visit_mask)
 {
@@ -105,6 +132,9 @@ int get_stack_info(unsigned long *stack, struct task_struct *task,
 	if (in_softirq_stack(stack, info))
 		goto recursion_check;
 
+	if (in_doublefault_stack(stack, info))
+		goto recursion_check;
+
 	goto unknown;
 
 recursion_check: