From: Samuel Just <sjust@redhat.com>
Date: Sat, 21 Dec 2019 02:04:47 +0000 (+0000)
Subject: fastbmap_allocator_impl: avoid std::vector[] for oob index
X-Git-Tag: v15.1.0~91^2~1
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=9c89b16a8c3dfefd3a2d93dea533350377178ff5;p=ceph.git

fastbmap_allocator_impl: avoid std::vector[] for oob index

This was relatively harmless as the pointer won't actually be
dereferenced, but it runs afoul of std::vector's bounds checks with
_GLIBCXX_ASSERTIONS enabled.

Signed-off-by: Samuel Just <sjust@redhat.com>
---

diff --git a/src/os/bluestore/fastbmap_allocator_impl.cc b/src/os/bluestore/fastbmap_allocator_impl.cc
index 22e18c7141bf..441a185d5c72 100644
--- a/src/os/bluestore/fastbmap_allocator_impl.cc
+++ b/src/os/bluestore/fastbmap_allocator_impl.cc
@@ -286,7 +286,7 @@ void AllocatorLevel01Loose::_mark_alloc_l0(int64_t l0_pos_start,
 
   int64_t pos = l0_pos_start;
   slot_t bits = (slot_t)1 << (l0_pos_start % d0);
-  slot_t* val_s = &l0[pos / d0];
+  slot_t* val_s = l0.data() + (pos / d0);
   int64_t pos_e = std::min(l0_pos_end, p2roundup<int64_t>(l0_pos_start + 1, d0));
   while (pos < pos_e) {
     (*val_s) &= ~bits;