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fix invalid memory access bug in tidbGreatestString #8613

Merged
merged 3 commits into from
Dec 28, 2023
Merged

fix invalid memory access bug in tidbGreatestString #8613

merged 3 commits into from
Dec 28, 2023

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windtalker
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@windtalker windtalker commented Dec 27, 2023 •
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What problem does this PR solve?

Issue Number: close #8604

Problem Summary:
In LeastGreatestStringImpl::mergeImpl, it use memcpy to copy data to the target column, however, it does not reserve enough space before LeastGreatestStringImpl::mergeImpl, so there maybe some invalid memory read/write in this function, and will cause issue randomly.

What is changed and how it works?

Check List

Tests

  • Unit test
  • Integration test
  • Manual test (add detailed scripts or steps below)
  • No code

Side effects

  • Performance regression: Consumes more CPU
  • Performance regression: Consumes more Memory
  • Breaking backward compatibility

Documentation

  • Affects user behaviors
  • Contains syntax changes
  • Contains variable changes
  • Contains experimental features
  • Changes MySQL compatibility

Release note

Fix random invalid memory access in greatest/leatest function containing constant string arguments

@ti-chi-bot ti-chi-bot bot added do-not-merge/needs-triage-completed release-note-none Denotes a PR that doesn't merit a release note. size/L Denotes a PR that changes 100-499 lines, ignoring generated files. needs-cherry-pick-release-7.1 Should cherry pick this PR to release-7.1 branch. needs-cherry-pick-release-7.5 Should cherry pick this PR to release-7.5 branch. and removed do-not-merge/needs-triage-completed labels Dec 27, 2023
@windtalker windtalker changed the title fix bug fix invalid memory access bug in tidbGreatestString Dec 27, 2023
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/hold

@ti-chi-bot ti-chi-bot bot added the do-not-merge/hold Indicates that a PR should not merge because someone has issued a /hold command. label Dec 27, 2023
gengliqi
gengliqi approved these changes Dec 27, 2023
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Rest LGTM

dbms/src/Functions/LeastGreatest.h Outdated
size_t size = std::min(a_size, b_size);
memcpy(&c_data[pre_offset], &b_data[0], size);
c_offsets[i] = pre_offset + size + 1;
append_data(&a_data[0], a_size);
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Suggested change
append_data(&a_data[0], a_size);
append_data(a_data, a_size);

dbms/src/Functions/LeastGreatest.h Outdated
memcpy(&c_data[pre_offset], &b_data[0], b_size);
c_offsets[i] = pre_offset + b_size + 1;
assert(res > 0 || a_size == b_size);
append_data(&b_data[0], b_size);
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Suggested change
append_data(&b_data[0], b_size);
append_data(b_data, b_size);

dbms/src/Functions/LeastGreatest.h Outdated
memcpy(&c_data[pre_offset], &b_data[0], size);
c_offsets[i] = pre_offset + size + 1;
}
append_data(&b_data[0], b_size);
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Suggested change
append_data(&b_data[0], b_size);
append_data(b_data, b_size);

dbms/src/Functions/LeastGreatest.h Outdated
memcpy(&c_data[pre_offset], &a_data[0], a_size);
c_offsets[i] = pre_offset + a_size + 1;
assert(res > 0 || a_size == b_size);
append_data(&a_data[0], a_size);
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Suggested change
append_data(&a_data[0], a_size);
append_data(a_data, a_size);

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Done

@ti-chi-bot ti-chi-bot bot added needs-1-more-lgtm Indicates a PR needs 1 more LGTM. approved labels Dec 27, 2023
yibin87
yibin87 approved these changes Dec 28, 2023
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LGTM

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ti-chi-bot bot commented Dec 28, 2023

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gengliqi, yibin87

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@ti-chi-bot ti-chi-bot bot added lgtm and removed needs-1-more-lgtm Indicates a PR needs 1 more LGTM. labels Dec 28, 2023
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ti-chi-bot bot commented Dec 28, 2023

[LGTM Timeline notifier]

Timeline:

  • 2023-12-27 10:50:02.319327827 +0000 UTC m=+1649293.356554740: ☑️ agreed by gengliqi.
  • 2023-12-28 01:42:05.645555848 +0000 UTC m=+1702816.682782774: ☑️ agreed by yibin87.

@windtalker windtalker force-pushed the fix_memory_issue_in_greatest_string branch from 250ff76 to b704275 Compare December 28, 2023 02:14
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/hold cancel

@ti-chi-bot ti-chi-bot bot removed the do-not-merge/hold Indicates that a PR should not merge because someone has issued a /hold command. label Dec 28, 2023
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/run-all-tests

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ti-chi-bot bot commented Dec 28, 2023

@windtalker: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

trigger some heavy tests which will not run always when PR updated.

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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@windtalker
fix bug
3a7e04f 
Signed-off-by: xufei <[email protected]>
@windtalker
fix build and adress comments
5e496f8 
Signed-off-by: xufei <[email protected]>
@windtalker
fix test
bb70050 
Signed-off-by: xufei <[email protected]>
@windtalker windtalker force-pushed the fix_memory_issue_in_greatest_string branch from 5ab4ff3 to bb70050 Compare December 28, 2023 08:16
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/run-all-tests

@ti-chi-bot ti-chi-bot bot merged commit 10f9542 into pingcap:master Dec 28, 2023
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@ti-chi-bot ti-chi-bot mentioned this pull request Dec 28, 2023
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In response to a cherrypick label: new pull request created to branch release-7.1: #8619.

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In response to a cherrypick label: new pull request created to branch release-7.5: #8620.

@ti-chi-bot ti-chi-bot mentioned this pull request Dec 28, 2023
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@windtalker windtalker deleted the fix_memory_issue_in_greatest_string branch December 28, 2023 09:26
ti-chi-bot bot pushed a commit that referenced this pull request Jan 4, 2024
@ti-chi-bot
fix invalid memory access bug in tidbGreatestString (#8613) (#8619)
8fd7544 
close #8604
ti-chi-bot bot pushed a commit that referenced this pull request Jan 4, 2024
@ti-chi-bot
fix invalid memory access bug in tidbGreatestString (#8613) (#8620)
7efee67 
close #8604
@ti-chi-bot ti-chi-bot bot added release-note Denotes a PR that will be considered when it comes time to generate release notes. and removed release-note-none Denotes a PR that doesn't merit a release note. labels Jan 10, 2024
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@gengliqi gengliqi gengliqi approved these changes

@yibin87 yibin87 yibin87 approved these changes

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approved lgtm needs-cherry-pick-release-7.1 Should cherry pick this PR to release-7.1 branch. needs-cherry-pick-release-7.5 Should cherry pick this PR to release-7.5 branch. release-note Denotes a PR that will be considered when it comes time to generate release notes. size/L Denotes a PR that changes 100-499 lines, ignoring generated files.
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Successfully merging this pull request may close these issues.

Memory control overestimates memory usage when executing SQL with LEAST(...) or GREATEST(...)
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