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Differential D145821

[libc][NFC] add an atof test for a fuzz failure
ClosedPublic

Authored by michaelrj on Mar 10 2023, 11:55 AM.

Details

Reviewers
lntue
sivachandra
Commits
rG7aec387dbec7: [libc][NFC] add an atof test for a fuzz failure
Summary

The differential fuzzer found that glibc and our libc disagree on the
result for "0x30000002222225p-1077", with ours being rounded up and
theirs rounded down. Ours is more correct for the nearest rounding mode,
so only a test is added.

Diff Detail

Event Timeline

michaelrj created this revision.Mar 10 2023, 11:55 AM
Herald added projects: Restricted Project, Restricted Project. · View Herald TranscriptMar 10 2023, 11:55 AM
Herald added subscribers: libc-commits, ecnelises, tschuett. · View Herald Transcript
michaelrj requested review of this revision.Mar 10 2023, 11:55 AM
Harbormaster completed remote builds in B218742: Diff 504241.Mar 10 2023, 12:16 PM
lntue accepted this revision.Mar 10 2023, 12:45 PM
This revision is now accepted and ready to land.Mar 10 2023, 12:45 PM
lntue added inline comments.Mar 10 2023, 12:46 PM
libc/test/src/stdlib/strtod_test.cpp
195–196

Can you add the version of glibc, and include the link to glibc bug report if available?

michaelrj updated this revision to Diff 505196.Mar 14 2023, 11:34 AM
michaelrj marked an inline comment as done.

add more information on the glibc bug

sivachandra accepted this revision.Mar 14 2023, 11:37 AM
sivachandra added a subscriber: sivachandra.
sivachandra added inline comments.
libc/test/src/stdlib/strtod_test.cpp
195

Replace with (not tested with lower versions).

michaelrj updated this revision to Diff 505199.Mar 14 2023, 11:42 AM

adjust phrasing before landing.

michaelrj marked an inline comment as done.Mar 14 2023, 11:42 AM
This revision was landed with ongoing or failed builds.Mar 14 2023, 11:43 AM
Closed by commit rG7aec387dbec7: [libc][NFC] add an atof test for a fuzz failure (authored by michaelrj). · Explain Why
This revision was automatically updated to reflect the committed changes.
michaelrj added a commit: rG7aec387dbec7: [libc][NFC] add an atof test for a fuzz failure.
Harbormaster completed remote builds in B219427: Diff 505199.Mar 14 2023, 12:00 PM

Revision Contents

PathSize
libc/
test/
src/
stdlib/
5 lines

Diff 505199

libc/test/src/stdlib/strtod_test.cpp

Show First 20 Lines • Show All 185 Lines • ▼ Show 20 LinesTEST_F(LlvmLibcStrToDTest, FuzzFailures) {
run_test( run_test(
"44444444444444444444444444444444444444444444444444A44444444444444444" "44444444444444444444444444444444444444444444444444A44444444444444444"
"44444444444*\x99\xff\xff\xff\xff", "44444444444*\x99\xff\xff\xff\xff",
50, uint64_t(0x4a3e68fdd0e0b2d8)); 50, uint64_t(0x4a3e68fdd0e0b2d8));
run_test("-NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNKNNNNNNNNNNNNNNNNNN?" run_test("-NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNKNNNNNNNNNNNNNNNNNN?"
"NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN?", "NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN?",
0, uint64_t(0)); 0, uint64_t(0));
run_test("0x.666E40", 9, uint64_t(0x3fd99b9000000000)); run_test("0x.666E40", 9, uint64_t(0x3fd99b9000000000));
// glibc version 2.36 and higher (not tested with lower versions) disagrees
sivachandraUnsubmitted
Done
ReplyInline Actions

Replace with (not tested with lower versions).

sivachandra: Replace with `(not tested with lower versions)`.
// with this result, but ours is correct for the nearest rounding mode. See
lntueUnsubmitted
Done
ReplyInline Actions

Can you add the version of glibc, and include the link to glibc bug report if available?

lntue: Can you add the version of glibc, and include the link to glibc bug report if available?
// this bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30220
run_test("0x30000002222225p-1077", 22, uint64_t(0x0006000000444445), ERANGE);
} }