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-rw-r--r--arch/x86/mm/fault.c21
1 files changed, 16 insertions, 5 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 2a9ea3aee49..94c4e726219 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -782,6 +782,15 @@ static inline int access_error(unsigned long error_code, int write,
return 0;
}
+static int fault_in_kernel_space(unsigned long address)
+{
+#ifdef CONFIG_X86_32
+ return address >= TASK_SIZE;
+#else /* !CONFIG_X86_32 */
+ return address >= TASK_SIZE64;
+#endif /* CONFIG_X86_32 */
+}
+
/*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate
@@ -822,11 +831,7 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
* (error_code & 4) == 0, and that the fault was not a
* protection error (error_code & 9) == 0.
*/
-#ifdef CONFIG_X86_32
- if (unlikely(address >= TASK_SIZE)) {
-#else
- if (unlikely(address >= TASK_SIZE64)) {
-#endif
+ if (unlikely(fault_in_kernel_space(address))) {
if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
vmalloc_fault(address) >= 0)
return;
@@ -898,6 +903,12 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
return;
}
down_read(&mm->mmap_sem);
+ } else {
+ /*
+ * The above down_read_trylock() might have succeeded in which
+ * case we'll have missed the might_sleep() from down_read().
+ */
+ might_sleep();
}
vma = find_vma(mm, address);