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Posted to reviews@kudu.apache.org by "Adar Dembo (Code Review)" <ge...@cloudera.org> on 2018/11/08 20:28:18 UTC

[kudu-CR] KUDU-2378: fix another aligned load crash

Hello Alexey Serbin, Grant Henke, Todd Lipcon,

I'd like you to do a code review. Please visit

    http://gerrit.cloudera.org:8080/11911

to review the following change.


Change subject: KUDU-2378: fix another aligned load crash
......................................................................

KUDU-2378: fix another aligned load crash

The TestKuduBackup.testRandomBackupAndRestore test from the kudu-backup
project would crash a TSAN master from time to time, with a stack trace
ending in Variant::Reset. After some debugging, this turned out to be a
holdover from KUDU-2378, where clang emitted a movaps (Aligned Load)
instruction on a value that wasn't aligned. The holdover was missed
because it was a static_cast (the original search covered
reinterpret_casts); I did a search for other bad casts but found none.

Why TSAN? Probably because it's the only build to use libc++, whose
std::string uses the Small String Optimization to embed the data into the
string itself, thus raising the possibility of the string's data being
unaligned. By comparison, libstdc++'s COW std::string uses a separate
allocation for string data, which is likely always 16-byte aligned.

The patch includes a unit test that isn't totally necessary, but was a
useful way to repro the crash in relative isolation.

Change-Id: I13e23a9d88db878071faeff7b9de06d1bdd98357
---
M src/kudu/common/types.h
M src/kudu/master/master-test.cc
2 files changed, 21 insertions(+), 1 deletion(-)



  git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/11/11911/1
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To view, visit http://gerrit.cloudera.org:8080/11911
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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I13e23a9d88db878071faeff7b9de06d1bdd98357
Gerrit-Change-Number: 11911
Gerrit-PatchSet: 1
Gerrit-Owner: Adar Dembo <ad...@cloudera.com>
Gerrit-Reviewer: Alexey Serbin <as...@cloudera.com>
Gerrit-Reviewer: Grant Henke <gr...@apache.org>
Gerrit-Reviewer: Todd Lipcon <to...@apache.org>

[kudu-CR] KUDU-2378: fix another aligned load crash

Posted by "Todd Lipcon (Code Review)" <ge...@cloudera.org>.

Todd Lipcon has posted comments on this change. ( http://gerrit.cloudera.org:8080/11911 )

Change subject: KUDU-2378: fix another aligned load crash
......................................................................


Patch Set 2:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/11911/2/src/kudu/common/types.h
File src/kudu/common/types.h:

http://gerrit.cloudera.org:8080/#/c/11911/2/src/kudu/common/types.h@702
PS2, Line 702:         numeric_.u64 = *static_cast<const uint64_t *>(value);
mind fixing all these others, too, so that whenever some poor soul tries to port kudu to Alpha or something, it won't crash?



-- 
To view, visit http://gerrit.cloudera.org:8080/11911
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I13e23a9d88db878071faeff7b9de06d1bdd98357
Gerrit-Change-Number: 11911
Gerrit-PatchSet: 2
Gerrit-Owner: Adar Dembo <ad...@cloudera.com>
Gerrit-Reviewer: Alexey Serbin <as...@cloudera.com>
Gerrit-Reviewer: Grant Henke <gr...@apache.org>
Gerrit-Reviewer: Kudu Jenkins (120)
Gerrit-Reviewer: Tidy Bot (241)
Gerrit-Reviewer: Todd Lipcon <to...@apache.org>
Gerrit-Comment-Date: Thu, 08 Nov 2018 22:18:35 +0000
Gerrit-HasComments: Yes

[kudu-CR] KUDU-2378: fix another aligned load crash

Posted by "Todd Lipcon (Code Review)" <ge...@cloudera.org>.

Todd Lipcon has posted comments on this change. ( http://gerrit.cloudera.org:8080/11911 )

Change subject: KUDU-2378: fix another aligned load crash
......................................................................


Patch Set 4: Code-Review+2


-- 
To view, visit http://gerrit.cloudera.org:8080/11911
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I13e23a9d88db878071faeff7b9de06d1bdd98357
Gerrit-Change-Number: 11911
Gerrit-PatchSet: 4
Gerrit-Owner: Adar Dembo <ad...@cloudera.com>
Gerrit-Reviewer: Adar Dembo <ad...@cloudera.com>
Gerrit-Reviewer: Alexey Serbin <as...@cloudera.com>
Gerrit-Reviewer: Grant Henke <gr...@apache.org>
Gerrit-Reviewer: Tidy Bot (241)
Gerrit-Reviewer: Todd Lipcon <to...@apache.org>
Gerrit-Comment-Date: Fri, 09 Nov 2018 02:07:31 +0000
Gerrit-HasComments: No