piman@, awesome to see your fuzzer in action! Could you please help to triage this?

This issue is a security regression. If you are not able to fix this quickly, please revert the change that introduced it.

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This is really awesome, thanks for writing this gpu command buffer fuzzer using libfuzzer unittests. I encourage you to write even more gpu fuzzers as our fuzzer coverage is not good in this area.

What kind of data does the target expect? I mean, is there any structure, or key words / magic constants?

If yes, we should definitely add a dictionary, it may significantly increase coverage.

Hey, look at that, it runs in ClusterFuzz :)

I have a fairly large corpus that I generated locally, which I will upload - it already found a bunch of stuff locally - this will significantly increase coverage.

There is some structure to the command buffer, but it is defined implicitly in code. I've been thinking of ways to generate a dictionary, and see if we can feed that to the fuzzer.

ClusterFuzz has detected this issue as fixed in range 406010:406169.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=6347013000265728

Fuzzer: libfuzzer_gpu_fuzzer
Job Type: libfuzzer_chrome_msan
Platform Id: linux

Crash Type: Use-of-uninitialized-value
Crash Address: 
Crash State:
  gpu::gles2::GLES2DecoderImpl::DoDrawBuffersEXT
  gpu::gles2::GLES2DecoderImpl::HandleDrawBuffersEXTImmediate
  gpu::error::Error gpu::gles2::GLES2DecoderImpl::DoCommandsImpl<false>
  
Recommended Security Severity: Medium

Regressed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_msan&range=405554:405701
Fixed: https://cluster-fuzz.appspot.com/revisions?job=libfuzzer_chrome_msan&range=406010:406169

Minimized Testcase (0.02 Kb): https://cluster-fuzz.appspot.com/download/AMIfv96s9KBa-7NC9rEYOY01gvvdW88nZEFHNdO1_HxzX7TSfKPgaHo0BQxu0f9Dit4ACRDYayxxZoX9uFZ3i6KnUV4ezCxIa2lBlLvuVF7DqNYeVgudtrqt5dMflqclGEBISep0_mkdTfCVwVEHRP88UDUaYZZeaw?testcase_id=6347013000265728

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.

Even though bugdroid forgot to update here - https://chromium.googlesource.com/chromium/src/+/19ea5e66d31e815c7689977de71222e1b0984c92%5E%21/#F0, clusterfuzz didn't forget to verify :)

This bug has been closed for more than 14 weeks. Removing security view restrictions.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot