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8263242: serviceability/sa/ClhsdbFindPC.java cannot find MaxJNILocalCapacity with ASLR #4075

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@plummercj plummercj commented May 17, 2021

The issue is that SA thought the library was smaller than it actually was, so SA refused to map an address to a symbol if the address was beyond what SA thought was the end of the library's memory range. However, the converse, mapping a symbol to an address, still worked even if the resulting address was thought to be out of range. This is because there was no range checking done in this case. Thus you could look up the address of a symbol, but then mapping the address back to a symbol might fail.

The root of the problem was using p_filesz instead of p_memsz when determining the size of a library segment, and there was also a rounding error once p_memsz was used, so it took a bit of extra logic to get the size computation just right. This comment in CR describes it best:

https://bugs.openjdk.java.net/browse/JDK-8263242?focusedCommentId=14408953&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14408953

There are also a bunch of p_filesz references in ps_core.c that should probably be p_memsz. However, I did some printfs and found the values to always be the same within core files, so decided not to risk making this change.


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  • JDK-8263242: serviceability/sa/ClhsdbFindPC.java cannot find MaxJNILocalCapacity with ASLR

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@bridgekeeper bridgekeeper bot commented May 17, 2021

👋 Welcome back cjplummer! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

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@openjdk openjdk bot added the rfr label May 17, 2021
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@openjdk openjdk bot commented May 17, 2021

@plummercj The following label will be automatically applied to this pull request:

  • serviceability

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

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@mlbridge mlbridge bot commented May 17, 2021

Webrevs

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@openjdk openjdk bot commented May 18, 2021

@plummercj This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8263242: serviceability/sa/ClhsdbFindPC.java cannot find MaxJNILocalCapacity with ASLR

Reviewed-by: kevinw, ysuenaga

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 10 new commits pushed to the master branch:

  • da7c846: 8264408: test_oopStorage no longer needs to disable some tests on WIN32
  • f6c2891: 8267229: Split runtime/Metaspace/elastic test configurations for better scalability
  • b60975d: 8267237: ARM32: bad AD file in matcher.cpp after 8266810
  • 905b41a: 8265711: C1: Intrinsify Class.getModifier method
  • 554caf3: 8251392: Consolidate Metaspace Statistics
  • 3e97b07: 8267116: Lanai: Incorrect AlphaComposite for VolatileImage graphics
  • cd1c17c: 8266404: Fatal error report generated with -XX:+CrashOnOutOfMemoryError should not contain suggestion to submit a bug report
  • 2effdd1: 8267112: JVMCI compiler modules should be kept upgradable
  • da4dfde: 8264777: Overload optimized FileInputStream::readAllBytes
  • 3b11d81: 8266742: Check W^X state on possible safepoint

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

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@openjdk openjdk bot added the ready label May 18, 2021
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@plummercj plummercj commented May 18, 2021

Thanks for the reviews!

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@plummercj plummercj commented May 18, 2021

/integrate

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@openjdk openjdk bot closed this May 18, 2021
@openjdk openjdk bot added integrated and removed ready rfr labels May 18, 2021
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@openjdk openjdk bot commented May 18, 2021

@plummercj Since your change was applied there have been 18 commits pushed to the master branch:

  • e6705c0: 8266949: Check possibility to disable OperationTimedOut on Unix
  • b92c5a4: 8265292: [macos_aarch64] java/foreign/TestDowncall.java crashes with SIGBUS
  • fadf580: 8262952: [macos_aarch64] os::commit_memory failure
  • f8f40ab: 8230486: G1BarrierSetAssembler::g1_write_barrier_post unnecessarily pushes/pops new_val
  • 9d168e2: 8266973: Migrate to ClassHierarchyIterator when enumerating subclasses
  • 02507bc: 8267166: Remove test file vmTestbase/vm/mlvm/tools/LoadClass.java
  • ce88b33: 8266615: C2 incorrectly folds subtype checks involving an interface array
  • 894547d: 8266897: com/sun/net/httpserver/FilterTest.java fails intermittently with AssertionError
  • da7c846: 8264408: test_oopStorage no longer needs to disable some tests on WIN32
  • f6c2891: 8267229: Split runtime/Metaspace/elastic test configurations for better scalability
  • ... and 8 more: https://git.openjdk.java.net/jdk/compare/79b39445f6fcd005744c5de89ba2cd2ed5bc0a54...master

Your commit was automatically rebased without conflicts.

Pushed as commit 10236e7.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

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