8268165: AsyncLogging will crash if rotate() fails

[navyxliu]

LogFileOutput::rotate() may leave _stream NULL because os::fopen() may return NULL due to space or inode limitations. AsyncLogWriter::write() calls LogFileOutput::write_blocking() without null check. Null check is added to prevent from crashing.

---

Progress

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Issue

• JDK-8268165: AsyncLogging will crash if rotate() fails

Reviewers

• Yasumasa Suenaga (@YaSuenag - Reviewer)

Reviewing

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[bridgekeeper]

👋 Welcome back xliu! 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.

[openjdk]

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

• hotspot-runtime

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[navyxliu]

/summary LogFileOutput::rotate() may leave _stream NULL because os::fopen() may return NULL due to space or inode limitations. AsyncLogWriter::write() calls LogFileOutput::write_blocking() without null check. Null check is added to prevent from crashing.

[openjdk]

@navyxliu Setting summary to LogFileOutput::rotate() may leave _stream NULL because os::fopen() may return NULL due to space or inode limitations. AsyncLogWriter::write() calls LogFileOutput::write_blocking() without null check. Null check is added to prevent from crashing.

[mlbridge]

Webrevs

• 01: Full - Incremental (20c08df6)
• 00: Full (8e6cb1c8)

[navyxliu]

hi, @YaSuenag,
Could you take a look at this? It's an error-handling patch.

thanks,
--lx

[YaSuenag]

Looks good.

I wonder why we use semaphore instead of mutex for _rotation_semaphore, but it's not yours.

[openjdk]

@navyxliu 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:

8268165: AsyncLogging will crash if rotate() fails

LogFileOutput::rotate() may leave _stream NULL because os::fopen() may return NULL due to space or inode limitations.  AsyncLogWriter::write() calls LogFileOutput::write_blocking() without null check.  Null check is added to prevent from crashing.

Reviewed-by: 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 46 new commits pushed to the master branch:

• 341f676: 8267908: linux: thread_native_entry can scribble on stack frame
• f40c89e: 8267209: Child threads should defer logging to after child-parent handshake
• ae986bc: 8266749: AArch64: Backtracing broken on PAC enabled systems
• 36c4e5f: 8267187: Remove deprecated constructor for Log
• fc08af5: 8174222: LambdaMetafactory: validate inputs and improve documentation
• 5e557d8: 8266967: debug.cpp utility find() should print Java Object fields.
• c7c77fd: 8255557: Decouple GCM from CipherCore
• e546ae2: 8268296: ScopedMemoryAccess build error with readonly filesystems
• 81600dc: 8191441: (Process) add Readers and Writer access to java.lang.Process streams
• 7e55569: 8261549: Adjust memory size in MTLTexurePool.m
• ... and 36 more: https://git.openjdk.java.net/jdk/compare/20b631278c0c89ccd9c16f2a29d47eb8414aacd5...master

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.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@YaSuenag) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[navyxliu]

Looks good.

I wonder why we use semaphore instead of mutex for _rotation_semaphore, but it's not yours.

Thanks for reviewing it.

I can try to answer this. Synchronous logging writing may happen anywhere and anytime.
hotspot's mutex requires Thread::current(). We can't assume that in very early stage or very late stage, or it will fail this assertion.

  assert(current != NULL, "Thread::current() called on detached thread");

eg. this logsite is invoked after delete thread;.
https://github.com/openjdk/jdk/blob/master/src/hotspot/share/runtime/threadSMR.cpp#L1027

Semaphore doesn't have this constraint.

[YaSuenag]

I can try to answer this. Synchronous logging writing may happen anywhere and anytime.
hotspot's mutex requires Thread::current(). We can't assume that in very early stage or very late stage, or it will fail this assertion.

  assert(current != NULL, "Thread::current() called on detached thread");

eg. this logsite is invoked after delete thread;.
https://github.com/openjdk/jdk/blob/master/src/hotspot/share/runtime/threadSMR.cpp#L1027

Semaphore doesn't have this constraint.

Ah, I see. Thanks!

[navyxliu]

/integrate

[openjdk]

@navyxliu
Your change (at version 20c08df) is now ready to be sponsored by a Committer.

[YaSuenag]

/sponsor

[openjdk]

@YaSuenag @navyxliu Since your change was applied there have been 48 commits pushed to the master branch:

• fd91b2a: 8265440: IGV: make node selection more visible
• 81bad59: 8257774: G1: Trigger collect when free region count drops below threshold to prevent evacuation failures
• 341f676: 8267908: linux: thread_native_entry can scribble on stack frame
• f40c89e: 8267209: Child threads should defer logging to after child-parent handshake
• ae986bc: 8266749: AArch64: Backtracing broken on PAC enabled systems
• 36c4e5f: 8267187: Remove deprecated constructor for Log
• fc08af5: 8174222: LambdaMetafactory: validate inputs and improve documentation
• 5e557d8: 8266967: debug.cpp utility find() should print Java Object fields.
• c7c77fd: 8255557: Decouple GCM from CipherCore
• e546ae2: 8268296: ScopedMemoryAccess build error with readonly filesystems
• ... and 38 more: https://git.openjdk.java.net/jdk/compare/20b631278c0c89ccd9c16f2a29d47eb8414aacd5...master

Your commit was automatically rebased without conflicts.

Pushed as commit 8105478.

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

[mlbridge]

Mailing list message from David Holmes on hotspot-runtime-dev:

Xin, Yasumasa,

Please note that non-trivial changes in hotspot code require two reviews
before integration. [1]

Thanks,
David

[1] https://wiki.openjdk.java.net/display/HotSpot/Pushing+a+HotSpot+change

On 8/06/2021 5:23 pm, Xin Liu wrote:

[mlbridge]

Mailing list message from David Holmes on hotspot-runtime-dev:

Xin, Yasumasa,

Please note that non-trivial changes in hotspot code require two reviews
before integration. [1]

Thanks,
David

[1] https://wiki.openjdk.java.net/display/HotSpot/Pushing+a+HotSpot+change

On 8/06/2021 5:23 pm, Xin Liu wrote:

[YaSuenag]

Sorry, I will be careful.

[navyxliu]

hi, David,
I see. I read through that wiki. I will stick with two-reviewers rules in the future.