Looks similar to  bug 620659 , but stack-traces are different.

Not sure why I was assigned this. None of the commits in regression range is mine.

ClusterFuzz has detected this testcase as flaky and is unable to reproduce it in the original crash revision. Skipping fixed testing check and marking it as potentially fixed.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=4643757555449856

Fuzzer: libfuzzer_hunspell_fuzzer
Job Type: libfuzzer_chrome_ubsan
Platform Id: linux

Crash Type: Undefined-shift
Crash Address: 
Crash State:
  u8_u16
  SuggestMgr::ngram
  SuggestMgr::ngsuggest
  
Regressed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_ubsan&range=400697:402043

Minimized Testcase (0.00 Kb): https://cluster-fuzz.appspot.com/download/AMIfv94_6PfuoFtfStJuj3l5TVW7QtlukKKuuXJ_T8L80GtZAWuKbKBf3jMi1959f3uYhRDZplk53hz75rgqwsL3hsv_-UBIda6FIpuv2ETFkHbxZvXjxFUIJ2GqiahAJ3QPxsoe3w1XGj3NcNRFpkBMiT1Z3Du5Lw?testcase_id=4643757555449856

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

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

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=5410299356381184

Fuzzer: libfuzzer_hunspell_fuzzer
Job Type: libfuzzer_chrome_ubsan
Platform Id: linux

Crash Type: Undefined-shift
Crash Address: 
Crash State:
  u8_u16
  SuggestMgr::ngram
  SuggestMgr::ngsuggest
  
Regressed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_ubsan&range=400697:402043

Minimized Testcase (0.00 Kb): https://cluster-fuzz.appspot.com/download/AMIfv96SzVF1ggpqPTJy7dR28oy2UKzldrIsks72wHXK2S6HqWmryCim1qe8BxL7tqmMkGmHvry9oeQGtdzhHqJmPAamD89yYhotMp-eHfvc25IRzQ7ONahNz8l3E0_nM07LVeJ4-8FOcrQvTNkD8KNy4DvkQacAgw?testcase_id=5410299356381184

Filer: kavvaru

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

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=6496088236490752

Fuzzer: libfuzzer_hunspell_fuzzer
Job Type: libfuzzer_chrome_ubsan
Platform Id: linux

Crash Type: Undefined-shift
Crash Address: 
Crash State:
  u8_u16
  SuggestMgr::ngram
  SuggestMgr::ngsuggest
  
Regressed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_ubsan&range=400697:402043

Minimized Testcase (0.00 Kb): https://cluster-fuzz.appspot.com/download/AMIfv94gBy-5HhLwhI9fFAdm9_UIJ9xT02mzBesZ7uOKiw4YkXi_1M-qpfHO4_vbTBeFTl-6kEGlr9ehYHrkSbPpS-XgDAVTMpzfMCpngA9jou9JOTscqRUa0XNB5tmQaE-pmvfRc0IIhzvfd5gvOKDqdmzdBeQp-w?testcase_id=6496088236490752

Filer: rnimmagadda

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

Suspecting:

Author: mmoroz
Project: chromium
Changelist: https://chromium.googlesource.com/chromium/src//+/cf3e7e2ae4087ed941106aee0411c786dc4f112d
Time: Fri Jun 24 11:06:02 2016
File hunspell_fuzzer.cc is changed in this cl (and is part of stack frame #4, "LLVMFuzzerTestOneInput")
Minimum distance from crash line to modified line: 3. (file: hunspell_fuzzer.cc, crashed on: 21, modified: 18).

@mmoroz: Could you please look into this issue.

Thank you.

groby@, could you please help to triage this?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e87c5a27a35c73cc8b099742d914d79d7543deea

commit e87c5a27a35c73cc8b099742d914d79d7543deea
Author: krb <krb@chromium.org>
Date: Wed Aug 24 16:57:21 2016

Changed signed char* to unsigned char*, fuzzer fix

Fuzzer reports undefined behavior precisely at the locations where
it performs a left shift on a signed char. Changing it to a regular
char makes the errors go away.

Since the function is doing lots of bit manipulation, a signed char
seems inappropriate anyways. All spellcheck tests pass with regular
char.

The upstream github history (that I could find) shows that it has
always been signed, so I couldn't find a reason why it changed, if
it ever did.

BUG= 620659 , 624348 

Review-Url: https://codereview.chromium.org/2263263003
Cr-Commit-Position: refs/heads/master@{#414095}

[modify] https://crrev.com/e87c5a27a35c73cc8b099742d914d79d7543deea/third_party/hunspell/google.patch
[modify] https://crrev.com/e87c5a27a35c73cc8b099742d914d79d7543deea/third_party/hunspell/src/hunspell/csutil.cxx

ClusterFuzz has detected this issue as fixed in range 414068:414117.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=6496088236490752

Fuzzer: libfuzzer_hunspell_fuzzer
Job Type: libfuzzer_chrome_ubsan
Platform Id: linux

Crash Type: Undefined-shift
Crash Address: 
Crash State:
  u8_u16
  SuggestMgr::ngram
  SuggestMgr::ngsuggest
  
Regressed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_ubsan&range=400697:402043
Fixed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_ubsan&range=414068:414117

Minimized Testcase (0.00 Kb): https://cluster-fuzz.appspot.com/download/AMIfv94gBy-5HhLwhI9fFAdm9_UIJ9xT02mzBesZ7uOKiw4YkXi_1M-qpfHO4_vbTBeFTl-6kEGlr9ehYHrkSbPpS-XgDAVTMpzfMCpngA9jou9JOTscqRUa0XNB5tmQaE-pmvfRc0IIhzvfd5gvOKDqdmzdBeQp-w?testcase_id=6496088236490752

See https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reproducing.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 has detected this issue as fixed in range 414068:414117.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=5410299356381184

Fuzzer: libfuzzer_hunspell_fuzzer
Job Type: libfuzzer_chrome_ubsan
Platform Id: linux

Crash Type: Undefined-shift
Crash Address: 
Crash State:
  u8_u16
  SuggestMgr::ngram
  SuggestMgr::ngsuggest
  
Regressed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_ubsan&range=400697:402043
Fixed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_ubsan&range=414068:414117

Minimized Testcase (0.00 Kb): https://cluster-fuzz.appspot.com/download/AMIfv96SzVF1ggpqPTJy7dR28oy2UKzldrIsks72wHXK2S6HqWmryCim1qe8BxL7tqmMkGmHvry9oeQGtdzhHqJmPAamD89yYhotMp-eHfvc25IRzQ7ONahNz8l3E0_nM07LVeJ4-8FOcrQvTNkD8KNy4DvkQacAgw?testcase_id=5410299356381184

See https://chromium.googlesource.com/chromium/src/+/master/testing/libfuzzer/reproducing.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 is verified as fixed, closing issue.

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

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