Merge remote-tracking branch 'tip/x86/urgent' into efi-for-mingo

Conflicts:
	arch/x86/include/asm/efi.h

1 files changed, 13 insertions, 7 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 6dea040cc3a1..e7fa28bf3262 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1022,11 +1022,11 @@ static inline bool smap_violation(int error_code, struct pt_regs *regs)
  * routines.
  */
 static void __kprobes
-__do_page_fault(struct pt_regs *regs, unsigned long error_code)
+__do_page_fault(struct pt_regs *regs, unsigned long error_code,
+                unsigned long address)
 {
         struct vm_area_struct *vma;
         struct task_struct *tsk;
-        unsigned long address;
         struct mm_struct *mm;
         int fault;
         unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
@@ -1034,9 +1034,6 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code)
         tsk = current;
         mm = tsk->mm;
 
-        /* Get the faulting address: */
-        address = read_cr2();
-
         /*
          * Detect and handle instructions that would cause a page fault for
          * both a tracked kernel page and a userspace page.
@@ -1252,9 +1249,11 @@ dotraplinkage void __kprobes
 do_page_fault(struct pt_regs *regs, unsigned long error_code)
 {
         enum ctx_state prev_state;
+        /* Get the faulting address: */
+        unsigned long address = read_cr2();
 
         prev_state = exception_enter();
-        __do_page_fault(regs, error_code);
+        __do_page_fault(regs, error_code, address);
         exception_exit(prev_state);
 }
 
@@ -1271,9 +1270,16 @@ dotraplinkage void __kprobes
 trace_do_page_fault(struct pt_regs *regs, unsigned long error_code)
 {
         enum ctx_state prev_state;
+        /*
+         * The exception_enter and tracepoint processing could
+         * trigger another page faults (user space callchain
+         * reading) and destroy the original cr2 value, so read
+         * the faulting address now.
+         */
+        unsigned long address = read_cr2();
 
         prev_state = exception_enter();
         trace_page_fault_entries(regs, error_code);
-        __do_page_fault(regs, error_code);
+        __do_page_fault(regs, error_code, address);
         exception_exit(prev_state);
 }