2 files changed, 31 insertions, 18 deletions

diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
index 52c13d2e011e..31113deeb7c0 100644
--- a/arch/x86/mm/fault_32.c
+++ b/arch/x86/mm/fault_32.c
@@ -36,10 +36,10 @@
  *      bit 3 == 1 means use of reserved bit detected
  *      bit 4 == 1 means fault was an instruction fetch
  */
-#define PF_PROT (1<<0)
+#define PF_PROT         (1<<0)
 #define PF_WRITE        (1<<1)
-#define PF_USER (1<<2)
-#define PF_RSVD (1<<3)
+#define PF_USER         (1<<2)
+#define PF_RSVD         (1<<3)
 #define PF_INSTR        (1<<4)
 
 static inline int notify_page_fault(struct pt_regs *regs)
@@ -460,11 +460,15 @@ bad_area_nosemaphore:
 
                 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
                     printk_ratelimit()) {
-                        printk("%s%s[%d]: segfault at %08lx ip %08lx "
-                            "sp %08lx error %lx\n",
-                            task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
-                            tsk->comm, task_pid_nr(tsk), address, regs->ip,
-                            regs->sp, error_code);
+                        printk(
+#ifdef CONFIG_X86_32
+                        "%s%s[%d]: segfault at %08lx ip %08lx sp %08lx error %lx\n",
+#else
+                        "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx\n",
+#endif
+                        task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+                        tsk->comm, task_pid_nr(tsk), address, regs->ip,
+                        regs->sp, error_code);
                 }
                 tsk->thread.cr2 = address;
                 /* Kernel addresses are always protection faults */
diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
index c6b3ad515cf1..c48d95c306df 100644
--- a/arch/x86/mm/fault_64.c
+++ b/arch/x86/mm/fault_64.c
@@ -440,8 +440,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
         if (!(vma->vm_flags & VM_GROWSDOWN))
                 goto bad_area;
         if (error_code & PF_USER) {
-                /* Allow userspace just enough access below the stack pointer
-                 * to let the 'enter' instruction work.
+                /*
+                 * Accessing the stack below %sp is always a bug.
+                 * The large cushion allows instructions like enter
+                 * and pusha to work.  ("enter $65535,$31" pushes
+                 * 32 pointers and then decrements %sp by 65535.)
                  */
                 if (address + 65536 + 32 * sizeof(unsigned long) < regs->sp)
                         goto bad_area;
@@ -522,10 +525,14 @@ bad_area_nosemaphore:
                 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
                     printk_ratelimit()) {
                         printk(
-                       "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx\n",
-                                        tsk->pid > 1 ? KERN_INFO : KERN_EMERG,
-                                        tsk->comm, tsk->pid, address, regs->ip,
-                                        regs->sp, error_code);
+#ifdef CONFIG_X86_32
+                        "%s%s[%d]: segfault at %08lx ip %08lx sp %08lx error %lx\n",
+#else
+                        "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx\n",
+#endif
+                        task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+                        tsk->comm, task_pid_nr(tsk), address, regs->ip,
+                        regs->sp, error_code);
                 }
 
                 tsk->thread.cr2 = address;
@@ -609,10 +616,12 @@ LIST_HEAD(pgd_list);
 
 void vmalloc_sync_all(void)
 {
-        /* Note that races in the updates of insync and start aren't
-           problematic:
-           insync can only get set bits added, and updates to start are only
-           improving performance (without affecting correctness if undone). */
+        /*
+         * Note that races in the updates of insync and start aren't
+         * problematic: insync can only get set bits added, and updates to
+         * start are only improving performance (without affecting correctness
+         * if undone).
+         */
         static DECLARE_BITMAP(insync, PTRS_PER_PGD);
         static unsigned long start = VMALLOC_START & PGDIR_MASK;
         unsigned long address;