CRASH in tool.drcacheoff.raw-zlib test: bug in zlib_istream.h

The tool.drcacheoff.raw-zlib test crashed on Jenkins but I don't think this is limited to AArch64:

70/84 Test #220: code_api|tool.drcacheoff.raw-zlib ...............................***Failed    0.47 sec
Running cmd |/var/lib/jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_release-external-64/bin64/drrun;-s;90;-quiet;-killpg;-stderr_mask;0xC;-dumpcore_mask;0;-code_api;-t;drcachesim;-offline;-subdir_prefix;tool.drcacheoff.raw-zlib;-raw_compress;zlib;--;/var/lib/jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_release-external-64/suite/tests/bin/simple_app|
Running postcmd |/var/lib/jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_release-external-64/clients/bin64/drcachesim;-indir;/var/lib/jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_release-external-64/suite/tests/tool.drcacheoff.raw-zlib.simple_app.3622551.1757.dir|
CMake Error at /var/lib/jenkins/workspace/DynamoRIO-AArch64-Precommit/suite/tests/runmulti.cmake:108 (message):
  *** postcmd failed (Segmentation fault): ***

On the same machine I managed to reproduce but only on the 2nd try. Once I had a raw file that reproduces, it is a deterministic crash in raw2trace.

 523692 [drmemtrace]: Thread 3631869 timestamp 0x002f461fc314fe80
<...>
 561733 [drmemtrace]: Appending 5 instrs in bb 0xfffd8833c5f0 in mod 7 +0x95f0 = /usr/lib/aarch64-linux-gnu/ld-2.31.so
 561734 [drmemtrace]: Caching last block summary 0xfffd8006d460 for 0xfffd8833c5f0
 561735   0x0000ffff99a9c5f0 ldr    (%x23)[4byte] -> %w1
 561736 [drmemtrace]: Using last block summary 0xfffd8006d460 for 0xfffd8833c5f0
 561737 [drmemtrace]: Appending delayed branch pc=0xffff99a9c5ec for thread 0
 561738 [drmemtrace]: [get_next_entry]: type=0 val=ffff99403d60
 561739 [drmemtrace]: Unreading last entry
 561740 [drmemtrace]: [get_next_entry]: type=0 val=ffff99403d60
 561741 [drmemtrace]: Appended memref type 0 size 4 to 0xffff99403d60
 561742 <Application /home/derek/dr/build/clients/bin64/drraw2trace (3633219).  Internal Error: DynamoRIO debug check failure: /home/derek/dr/src/core/unix/signal.c 561742 :5855 dcontext != GLOBAL_DCONTEXT

If I uncompress it works, so it looks like a bug in zlib_istream.h.

zlib-flate -uncompress < xx/tool.drcacheoff.raw-zlib.simple_app.3631869.4821.dir/raw/tool.drcacheoff.raw-zlib.simple_app.3631869.6202.raw.zlib > xx/tool.drcacheoff.raw-zlib.simple_app.3631869.4821.dir/raw/uncompressed.raw


 561733 [drmemtrace]: Appending 5 instrs in bb 0xfffd953f55f0 in mod 7 +0x95f0 = /usr/lib/aarch64-linux-gnu/ld-2.31.so
 561734 [drmemtrace]: Caching last block summary 0xfffd8c06d460 for 0xfffd953f55f0
 561735   0x0000ffff99a9c5f0 ldr    (%x23)[4byte] -> %w1
 561736 [drmemtrace]: Using last block summary 0xfffd8c06d460 for 0xfffd953f55f0
 561737 [drmemtrace]: Appending delayed branch pc=0xffff99a9c5ec for thread 0
 561738 [drmemtrace]: [get_next_entry]: type=0 val=ffff99403d60
 561739 [drmemtrace]: Unreading last entry
 561740 [drmemtrace]: [get_next_entry]: type=0 val=ffff99403d60
 561741 [drmemtrace]: Appended memref type 0 size 4 to 0xffff99403d60
 561742 [drmemtrace]: [get_next_entry]: type=1 val=2022000e00009604
 561743 [drmemtrace]: Unreading last entry
 561744   0x0000ffff99a9c5f4 orr    %wzr %w1 lsl $0x00 -> %w0
 561745 [drmemtrace]: Using last block summary 0xfffd8c06d460 for 0xfffd953f55f0
 561746 [drmemtrace]: [get_next_entry]: type=1 val=2022000e00009604
 561747 [drmemtrace]: Unreading last entry
 561748   0x0000ffff99a9c5f8 eor    %x0 %x28 lsl $0x00 -> %x0
 561749 [drmemtrace]: Using last block summary 0xfffd8c06d460 for 0xfffd953f55f0
 561750 [drmemtrace]: [get_next_entry]: type=1 val=2022000e00009604
 561751 [drmemtrace]: Unreading last entry
 561752   0x0000ffff99a9c5fc subs   %xzr %x0 lsr $0x01 -> %xzr
 561753 [drmemtrace]: Using last block summary 0xfffd8c06d460 for 0xfffd953f55f0
 561754 [drmemtrace]: [get_next_entry]: type=1 val=2022000e00009604
 561755 [drmemtrace]: Unreading last entry
 561756   0x0000ffff99a9c600 b.ne   $0x0000ffff99a9c5e8
 561757 [drmemtrace]: Using last block summary 0xfffd8c06d460 for 0xfffd953f55f0
 561758 [drmemtrace]: [get_next_entry]: type=1 val=2022000e00009604
 561759 [drmemtrace]: Unreading last entry
 561760 [drmemtrace]: [get_next_entry]: type=1 val=2022000e00009604
 561761 [drmemtrace]: Appending 17 instrs in bb 0xfffd953f5604 in mod 7 +0x9604 = /usr/lib/aarch64-linux-gnu/ld-2.31.so