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-rw-r--r--arch/arm/oprofile/backtrace.c46
1 files changed, 9 insertions, 37 deletions
diff --git a/arch/arm/oprofile/backtrace.c b/arch/arm/oprofile/backtrace.c
index df35c452a8bf..7c22c12618cc 100644
--- a/arch/arm/oprofile/backtrace.c
+++ b/arch/arm/oprofile/backtrace.c
@@ -49,42 +49,22 @@ static struct frame_tail* kernel_backtrace(struct frame_tail *tail)
static struct frame_tail* user_backtrace(struct frame_tail *tail)
{
- struct frame_tail buftail;
+ struct frame_tail buftail[2];
- /* hardware pte might not be valid due to dirty/accessed bit emulation
- * so we use copy_from_user and benefit from exception fixups */
- if (copy_from_user(&buftail, tail, sizeof(struct frame_tail)))
+ /* Also check accessibility of one struct frame_tail beyond */
+ if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
+ return NULL;
+ if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
return NULL;
- oprofile_add_trace(buftail.lr);
+ oprofile_add_trace(buftail[0].lr);
/* frame pointers should strictly progress back up the stack
* (towards higher addresses) */
- if (tail >= buftail.fp)
+ if (tail >= buftail[0].fp)
return NULL;
- return buftail.fp-1;
-}
-
-/* Compare two addresses and see if they're on the same page */
-#define CMP_ADDR_EQUAL(x,y,offset) ((((unsigned long) x) >> PAGE_SHIFT) \
- == ((((unsigned long) y) + offset) >> PAGE_SHIFT))
-
-/* check that the page(s) containing the frame tail are present */
-static int pages_present(struct frame_tail *tail)
-{
- struct mm_struct * mm = current->mm;
-
- if (!check_user_page_readable(mm, (unsigned long)tail))
- return 0;
-
- if (CMP_ADDR_EQUAL(tail, tail, 8))
- return 1;
-
- if (!check_user_page_readable(mm, ((unsigned long)tail) + 8))
- return 0;
-
- return 1;
+ return buftail[0].fp-1;
}
/*
@@ -118,7 +98,6 @@ static int valid_kernel_stack(struct frame_tail *tail, struct pt_regs *regs)
void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
{
struct frame_tail *tail;
- unsigned long last_address = 0;
tail = ((struct frame_tail *) regs->ARM_fp) - 1;
@@ -132,13 +111,6 @@ void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
return;
}
- while (depth-- && tail && !((unsigned long) tail & 3)) {
- if ((!CMP_ADDR_EQUAL(last_address, tail, 0)
- || !CMP_ADDR_EQUAL(last_address, tail, 8))
- && !pages_present(tail))
- return;
- last_address = (unsigned long) tail;
+ while (depth-- && tail && !((unsigned long) tail & 3))
tail = user_backtrace(tail);
- }
}
-