raw2trace failing on 32-bit vdso release build

[drmemtrace]: About to read thread 10509 at pos 1112504
[drmemtrace]: Appending 5 instrs in bb 0x0901621b in mod 5 +0x1050 = [vdso]
 0xf7d60050 push   %ecx %esp -> %esp 0xfffffffc(%esp)[4byte]
[drmemtrace]: Appended memref type 1 size 4 to 0xffdc28c0
 0xf7d60051 push   %edx %esp -> %esp 0xfffffffc(%esp)[4byte]
[drmemtrace]: Appended memref type 1 size 4 to 0xffdc28bc
 0xf7d60052 push   %ebp %esp -> %esp 0xfffffffc(%esp)[4byte]
[drmemtrace]: Appended memref type 1 size 4 to 0xffdc28b8
 0xf7d60053 mov    %esp -> %ebp
 0xf7d60055 sysenter  -> %esp
[drmemtrace]: About to read thread 10509 at pos 1112544
[drmemtrace]: Thread 10509 timestamp 0x002ec99be02737c0
[drmemtrace]: Next thread in timestamp order is 10509 @0x002ec99be02737c0
[drmemtrace]: About to read thread 10509 at pos 1112544
[drmemtrace]: Appended marker type 3 value 2
[drmemtrace]: About to read thread 19374 at pos 1112552
[drmemtrace]: Appending 4 instrs in bb 0x08e8b224 in mod 5 +0x1059 = [vdso]
 0xf7d60059 jmp    $0x62c8610d
ERROR: Conversion failed: invalid cti

Debug build:

interp: start_pc = 0xf7c11050
  0xf7c11050  51                   push   %ecx %esp -> %esp 0xfffffffc(%esp)[4byte]
  0xf7c11051  52                   push   %edx %esp -> %esp 0xfffffffc(%esp)[4byte]
  0xf7c11052  55                   push   %ebp %esp -> %esp 0xfffffffc(%esp)[4byte]
  0xf7c11053  89 e5                mov    %esp -> %ebp
  0xf7c11055  0f 34                sysenter  -> %esp
end_pc = 0xf7c11057

interp: start_pc = 0xf7c1105e
  0xf7c1105e  5d                   pop    %esp (%esp)[4byte] -> %ebp %esp
  0xf7c1105f  5a                   pop    %esp (%esp)[4byte] -> %edx %esp
  0xf7c11060  59                   pop    %esp (%esp)[4byte] -> %ecx %esp
  0xf7c11061  c3                   ret    %esp (%esp)[4byte] -> %esp
end_pc = 0xf7c11062

Debug build trace:

[drmemtrace]: Appending 5 instrs in bb 0x08976217 in mod 5 +0x1050 = [vdso]
 0xf7c3b050 push   %ecx %esp -> %esp 0xfffffffc(%esp)[4byte]
[drmemtrace]: Appended memref type 1 size 4 to 0xffd294d0
 0xf7c3b051 push   %edx %esp -> %esp 0xfffffffc(%esp)[4byte]
[drmemtrace]: Appended memref type 1 size 4 to 0xffd294cc
 0xf7c3b052 push   %ebp %esp -> %esp 0xfffffffc(%esp)[4byte]
[drmemtrace]: Appended memref type 1 size 4 to 0xffd294c8
 0xf7c3b053 mov    %esp -> %ebp
 0xf7c3b055 sysenter  -> %esp
[drmemtrace]: About to read thread 10747 at pos 1112600
[drmemtrace]: Thread 10747 timestamp 0x002ec99bf37a916d
[drmemtrace]: Next thread in timestamp order is 10747 @0x002ec99bf37a916d
[drmemtrace]: About to read thread 10747 at pos 1112600
[drmemtrace]: Appended marker type 3 value 4
[drmemtrace]: About to read thread 10747 at pos 1112608
[drmemtrace]: Appending 4 instrs in bb 0x08976220 in mod 5 +0x1059 = [vdso]
 0xf7c3b059 pop    %esp (%esp)[4byte] -> %ebp %esp
[drmemtrace]: Appended memref type 0 size 4 to 0xffd294c8
 0xf7c3b05a pop    %esp (%esp)[4byte] -> %edx %esp
[drmemtrace]: Appended memref type 0 size 4 to 0xffd294cc
 0xf7c3b05b pop    %esp (%esp)[4byte] -> %ecx %esp
[drmemtrace]: Appended memref type 0 size 4 to 0xffd294d0
 0xf7c3b05c ret    %esp (%esp)[4byte] -> %esp

Here's why: the recording is done at the end, and debug unhooks while release does not:

hooking vsyscall page @0xf7bb8059
Hello, world!
<Stopping application /work/dr/git/build_x86_dbg_tests/suite/tests/bin/simple_app (16227)>
unhooking vsyscall page @0xf7bb8059
recording vdso 0xf7bb7000-0x00002000

hooking vsyscall page @0xf7da8059
Hello, world!
recording vdso 0xf7da7000-0x00002000

Either need instru_offline to store vdso up front (pre-hook) or have release DR do the unhook.