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authorJames Morris <james.l.morris@oracle.com>2014-11-19 21:32:12 +1100
committerJames Morris <james.l.morris@oracle.com>2014-11-19 21:32:12 +1100
commitb10778a00d40b3d9fdaaf5891e802794781ff71c (patch)
tree6ba4cbac86eecedc3f30650e7f764ecf00c83898 /arch/x86/mm/fault.c
parent594081ee7145cc30a3977cb4e218f81213b63dc5 (diff)
parentbfe01a5ba2490f299e1d2d5508cbbbadd897bbe9 (diff)
Merge commit 'v3.17' into next
Diffstat (limited to 'arch/x86/mm/fault.c')
-rw-r--r--arch/x86/mm/fault.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 36642793e31..a2419468151 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -577,6 +577,8 @@ static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
static const char nx_warning[] = KERN_CRIT
"kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n";
+static const char smep_warning[] = KERN_CRIT
+"unable to execute userspace code (SMEP?) (uid: %d)\n";
static void
show_fault_oops(struct pt_regs *regs, unsigned long error_code,
@@ -597,6 +599,10 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code,
if (pte && pte_present(*pte) && !pte_exec(*pte))
printk(nx_warning, from_kuid(&init_user_ns, current_uid()));
+ if (pte && pte_present(*pte) && pte_exec(*pte) &&
+ (pgd_flags(*pgd) & _PAGE_USER) &&
+ (read_cr4() & X86_CR4_SMEP))
+ printk(smep_warning, from_kuid(&init_user_ns, current_uid()));
}
printk(KERN_ALERT "BUG: unable to handle kernel ");
@@ -1212,7 +1218,8 @@ good_area:
/*
* If for any reason at all we couldn't handle the fault,
* make sure we exit gracefully rather than endlessly redo
- * the fault:
+ * the fault. Since we never set FAULT_FLAG_RETRY_NOWAIT, if
+ * we get VM_FAULT_RETRY back, the mmap_sem has been unlocked.
*/
fault = handle_mm_fault(mm, vma, address, flags);