This issue looks similar to  bug 802242 , hence assigning to the same owner for more updates on this issue.

rharrison@ Could you please take a look in to this issue?

Thanks!

The following revision refers to this bug:
  https://pdfium.googlesource.com/pdfium/+/1e95aeadd33fc4a13f5579501f81b6d5edc7cc05

commit 1e95aeadd33fc4a13f5579501f81b6d5edc7cc05
Author: Ryan Harrison <rharrison@chromium.org>
Date: Mon Apr 23 21:09:33 2018

Pre-allocate more string buffers in barcode code

Another couple of examples where the slow down in the barcode code
can be fixed by reserving and thus pre-allocating the buffer that
backs the Widestring. Doing += in a tight loop caused reallocation
thrashing.

BUG= chromium:834630 

Change-Id: I48a802225351bcaf992c324732fddf81639b4898
Reviewed-on: https://pdfium-review.googlesource.com/31230
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>

[modify] https://crrev.com/1e95aeadd33fc4a13f5579501f81b6d5edc7cc05/fxbarcode/datamatrix/BC_EncoderContext.cpp
[modify] https://crrev.com/1e95aeadd33fc4a13f5579501f81b6d5edc7cc05/fxbarcode/datamatrix/BC_Base256Encoder.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/689eeb587dca4acd27d0a3177ee91369140be1c0

commit 689eeb587dca4acd27d0a3177ee91369140be1c0
Author: pdfium-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com <pdfium-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Date: Tue Apr 24 03:11:02 2018

Roll src/third_party/pdfium/ 4e4147ecc..2dca1cbf5 (2 commits)

https://pdfium.googlesource.com/pdfium.git/+log/4e4147eccd25..2dca1cbf5956

$ git log 4e4147ecc..2dca1cbf5 --date=short --no-merges --format='%ad %ae %s'
2018-04-23 dsinclair Cleanup CFX_XMLParser initialization
2018-04-23 rharrison Pre-allocate more string buffers in barcode code

Created with:
  roll-dep src/third_party/pdfium
BUG= chromium:834630 


The AutoRoll server is located here: https://pdfium-roll.skia.org

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


TBR=dsinclair@chromium.org

Change-Id: If2eb29c9bd23bb4d07f64549fcf72626d3c6bff6
Reviewed-on: https://chromium-review.googlesource.com/1025226
Commit-Queue: pdfium-chromium-autoroll <pdfium-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Reviewed-by: pdfium-chromium-autoroll <pdfium-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#552983}
[modify] https://crrev.com/689eeb587dca4acd27d0a3177ee91369140be1c0/DEPS

ClusterFuzz has detected this issue as fixed in range 552981:552990.

Detailed report: https://clusterfuzz.com/testcase?key=6257183210340352

Fuzzer: libFuzzer_pdf_cfx_barcode_fuzzer
Job Type: libfuzzer_chrome_msan
Platform Id: linux

Crash Type: Timeout (exceeds 25 secs)
Crash Address: 
Crash State:
  pdf_cfx_barcode_fuzzer
  
Sanitizer: memory (MSAN)

Regressed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_msan&range=550838:550851
Fixed: https://clusterfuzz.com/revisions?job=libfuzzer_chrome_msan&range=552981:552990

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=6257183210340352

See https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reference.md for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.

ClusterFuzz testcase 6257183210340352 is verified as fixed, so closing issue as verified.

If this is incorrect, please add ClusterFuzz-Wrong label and re-open the issue.