queue-3.18/xtensa-fix-return_address.patch

   1 From ada770b1e74a77fff2d5f539bf6c42c25f4784db Mon Sep 17 00:00:00 2001
   2 From: Max Filippov <jcmvbkbc@gmail.com>
   3 Date: Thu, 4 Apr 2019 11:08:40 -0700
   4 Subject: xtensa: fix return_address
   5
   6 From: Max Filippov <jcmvbkbc@gmail.com>
   7
   8 commit ada770b1e74a77fff2d5f539bf6c42c25f4784db upstream.
   9
  10 return_address returns the address that is one level higher in the call
  11 stack than requested in its argument, because level 0 corresponds to its
  12 caller's return address. Use requested level as the number of stack
  13 frames to skip.
  14
  15 This fixes the address reported by might_sleep and friends.
  16
  17 Cc: stable@vger.kernel.org
  18 Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
  19 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  20
  21 ---
  22  arch/xtensa/kernel/stacktrace.c |    6 +++++-
  23  1 file changed, 5 insertions(+), 1 deletion(-)
  24
  25 --- a/arch/xtensa/kernel/stacktrace.c
  26 +++ b/arch/xtensa/kernel/stacktrace.c
  27 @@ -107,10 +107,14 @@ static int return_address_cb(struct stac
  28         return 1;
  29  }
  30
  31 +/*
  32 + * level == 0 is for the return address from the caller of this function,
  33 + * not from this function itself.
  34 + */
  35  unsigned long return_address(unsigned level)
  36  {
  37         struct return_addr_data r = {
  38 -               .skip = level + 1,
  39 +               .skip = level,
  40         };
  41         walk_stackframe(stack_pointer(NULL), return_address_cb, &r);
  42         return r.addr;