1680837 - TSan fuzzing build fails to start

Status: RESOLVED FIXED

(Core :: Fuzzing, defect)

Description

[Tyson Smith [:tsmith]]

The TSan fuzzing builds crash on start up with this message:

-fsanitize-coverage=trace-pc-guard is no longer supported by libFuzzer.
Please either migrate to a compiler that supports -fsanitize=fuzzer
or use an older version of libFuzzer

Comment 1

[Christian Holler (:decoder)]

Can you please bisect this?

Comment 2

[Tyson Smith [:tsmith]]

The first failing build is: https://hg.mozilla.org/mozilla-central/rev/30a8286a26edd6f40ec6ea10e37b9a41ea2c7aaa
So my guess is bug 1660340.

Comment 3

[(Away)]

It would be interesting to know why we're passing trace-pc-guard in the first place, in other words why don't we take the early returns for "using tsan" or "clang >= 6" here: https://searchfox.org/mozilla-central/rev/1843375acbbca68127713e402be222350ac99301/build/moz.configure/toolchain.configure#2749,2758

Comment 4

[Christian Holler (:decoder)]

Attachment: Bug 1680837 - Fix libFuzzer gyp flags for nICEr. r?dmajor

The gyp flag logic in nICEr is supposed to ensure that the code is instrumented
for libFuzzer because we have a related fuzzing target. However, libFuzzer
instrumentation must be completely disabled for TSan due to incompatibility.
The current logic fails in doing so and incorrectly falls back to legacy
trace-pc instrumentation causing the TSan fuzzing build to fail on startup.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/46df9a612fb1
Fix libFuzzer gyp flags for nICEr. r=dmajor

Comment 6

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/46df9a612fb1