releases/3.19.7/powerpc-perf-cap-64bit-userspace-backtraces-to-perf_max_stack_depth.patch

   1 From 9a5cbce421a283e6aea3c4007f141735bf9da8c3 Mon Sep 17 00:00:00 2001
   2 From: Anton Blanchard <anton@samba.org>
   3 Date: Tue, 14 Apr 2015 07:51:03 +1000
   4 Subject: powerpc/perf: Cap 64bit userspace backtraces to PERF_MAX_STACK_DEPTH
   5
   6 From: Anton Blanchard <anton@samba.org>
   7
   8 commit 9a5cbce421a283e6aea3c4007f141735bf9da8c3 upstream.
   9
  10 We cap 32bit userspace backtraces to PERF_MAX_STACK_DEPTH
  11 (currently 127), but we forgot to do the same for 64bit backtraces.
  12
  13 Signed-off-by: Anton Blanchard <anton@samba.org>
  14 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
  15 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  16
  17 ---
  18  arch/powerpc/perf/callchain.c |    2 +-
  19  1 file changed, 1 insertion(+), 1 deletion(-)
  20
  21 --- a/arch/powerpc/perf/callchain.c
  22 +++ b/arch/powerpc/perf/callchain.c
  23 @@ -243,7 +243,7 @@ static void perf_callchain_user_64(struc
  24         sp = regs->gpr[1];
  25         perf_callchain_store(entry, next_ip);
  26
  27 -       for (;;) {
  28 +       while (entry->nr < PERF_MAX_STACK_DEPTH) {
  29                 fp = (unsigned long __user *) sp;
  30                 if (!valid_user_sp(sp, 1) || read_user_stack_64(fp, &next_sp))
  31                         return;