Fix IllegalReferenceCountException in AdaptiveByteBuf.deallocate()#16654
Merged
Conversation
…th JFR enabled When MagazineGroup.allocate() exhausts all magazine stripes under high contention, the bail-out path calls buf.release() on an AdaptiveByteBuf that was obtained from newBuffer() but never initialised via init(). The buffer's rootParent field is therefore null. With JFR recording active, deallocate() fires a FreeBufferEvent before clearing rootParent. AbstractBufferEvent.fill() calls buf.isDirect() which delegates to rootParent().isDirect(), and rootParent() throws IllegalReferenceCountException when the field is null. Guard the fill() call with a rootParent != null check so that the JFR event is silently skipped for never-initialised recycled buffers. No allocation ever occurred for such a buffer lifecycle, so there is nothing meaningful to record. Normally allocated buffers are unaffected.
franz1981
reviewed
Apr 16, 2026
a safe default when the buffer is not in an accessible state
chrisvest
approved these changes
Apr 19, 2026
Member
|
@gzsombor Did you sign the ICLA already? |
Contributor
Author
|
Yes, yesterday I've filled that form and submitted it! |
normanmaurer
approved these changes
Apr 20, 2026
netty-project-bot
pushed a commit
that referenced
this pull request
Apr 20, 2026
…16654) Motivation: Fix IllegalReferenceCountException in AdaptiveByteBuf.deallocate() when JFR enabled when lot's of buffer is used, we noticed this error: ``` io.netty.util.IllegalReferenceCountException at AdaptiveByteBuf.rootParent(AdaptivePoolingAllocator.java:1653) at AdaptiveByteBuf.isDirect(AdaptivePoolingAllocator.java:1725) at AbstractBufferEvent.fill(AbstractBufferEvent.java:44) at AdaptiveByteBuf.deallocate(AdaptivePoolingAllocator.java:2110) at AbstractReferenceCountedByteBuf.handleRelease(AbstractReferenceCountedByteBuf.java:93) at AbstractReferenceCountedByteBuf.release(AbstractReferenceCountedByteBuf.java:83) at AdaptivePoolingAllocator$MagazineGroup.allocate(AdaptivePoolingAllocator.java:431) at AdaptivePoolingAllocator.allocate(AdaptivePoolingAllocator.java:271) at AdaptiveByteBufAllocator.newDirectBuffer(AdaptiveByteBufAllocator.java:67) ``` Modification: When MagazineGroup.allocate() exhausts all magazine stripes under high contention, the bail-out path calls buf.release() on an AdaptiveByteBuf that was obtained from newBuffer() but never initialised via init(). The buffer's rootParent field is therefore null. With JFR recording active, deallocate() fires a FreeBufferEvent before clearing rootParent. AbstractBufferEvent.fill() calls buf.isDirect() which delegates to rootParent().isDirect(), and rootParent() throws IllegalReferenceCountException when the field is null. Result: JFR events are emitted even under pressure (cherry picked from commit 66568d1)
Contributor
|
Auto-port PR for 5.0: #16673 |
chrisvest
pushed a commit
that referenced
this pull request
Apr 21, 2026
…deallocate() (#16673) Auto-port of #16654 to 5.0 Cherry-picked commit: 66568d1 --- Motivation: Fix IllegalReferenceCountException in AdaptiveByteBuf.deallocate() when JFR enabled when lot's of buffer is used, we noticed this error: ``` io.netty.util.IllegalReferenceCountException at AdaptiveByteBuf.rootParent(AdaptivePoolingAllocator.java:1653) at AdaptiveByteBuf.isDirect(AdaptivePoolingAllocator.java:1725) at AbstractBufferEvent.fill(AbstractBufferEvent.java:44) at AdaptiveByteBuf.deallocate(AdaptivePoolingAllocator.java:2110) at AbstractReferenceCountedByteBuf.handleRelease(AbstractReferenceCountedByteBuf.java:93) at AbstractReferenceCountedByteBuf.release(AbstractReferenceCountedByteBuf.java:83) at AdaptivePoolingAllocator$MagazineGroup.allocate(AdaptivePoolingAllocator.java:431) at AdaptivePoolingAllocator.allocate(AdaptivePoolingAllocator.java:271) at AdaptiveByteBufAllocator.newDirectBuffer(AdaptiveByteBufAllocator.java:67) ``` Modification: When MagazineGroup.allocate() exhausts all magazine stripes under high contention, the bail-out path calls buf.release() on an AdaptiveByteBuf that was obtained from newBuffer() but never initialised via init(). The buffer's rootParent field is therefore null. With JFR recording active, deallocate() fires a FreeBufferEvent before clearing rootParent. AbstractBufferEvent.fill() calls buf.isDirect() which delegates to rootParent().isDirect(), and rootParent() throws IllegalReferenceCountException when the field is null. Result: JFR events are emitted even under pressure Co-authored-by: Zsombor <gzsombor@gmail.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
5 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Motivation:
Fix IllegalReferenceCountException in AdaptiveByteBuf.deallocate() when JFR enabled when lot's of buffer is used, we noticed this error:
Modification:
Result:
JFR events are emitted even under pressure