KAFKA-9835; Protect FileRecords.slice from concurrent write#8451
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ijuma
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Apr 8, 2020
| // handle integer overflow or if end is beyond the end of the file | ||
| if (end < 0 || end >= start + sizeInBytes()) | ||
| end = start + sizeInBytes(); | ||
| if (end < 0 || end > start + currentSizeInBytes) |
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Was the boundary check wrong? You changed >= to >.
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The common case that we would see this is when the limit matches the file end exactly. So changing this to > would also have fixed this problem for that case. I decided to remove it here though just because the equality check is redundant (if end == start + currentSizeInBytes, then there's no need to update it).
ijuma
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Nice catch, LGTM.
Let's please mention in the PR description that the common case for triggering this would be a read to the end of the log where the if check was interleaved with an append to the log.
| writerCompletion.get(); | ||
| readerCompletion.get(); | ||
| } finally { | ||
| executor.shutdownNow(); |
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It fails consistently for me without the fix.
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A read from the end of the log interleaved with a concurrent write can result in reading data above the expected read limit. In particular, this would allow a read above the high watermark. The root of the problem is consecutive calls to `sizeInBytes` in `FileRecords.slice` which do not account for an increase in size due to a concurrent write. This patch fixes the problem by using a single call to `sizeInBytes` and caching the result. Reviewers: Ismael Juma <ismael@juma.me.uk>
hachikuji
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A read from the end of the log interleaved with a concurrent write can result in reading data above the expected read limit. In particular, this would allow a read above the high watermark. The root of the problem is consecutive calls to `sizeInBytes` in `FileRecords.slice` which do not account for an increase in size due to a concurrent write. This patch fixes the problem by using a single call to `sizeInBytes` and caching the result. Reviewers: Ismael Juma <ismael@juma.me.uk>
qq619618919
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May 12, 2020
…#8451) A read from the end of the log interleaved with a concurrent write can result in reading data above the expected read limit. In particular, this would allow a read above the high watermark. The root of the problem is consecutive calls to `sizeInBytes` in `FileRecords.slice` which do not account for an increase in size due to a concurrent write. This patch fixes the problem by using a single call to `sizeInBytes` and caching the result. Reviewers: Ismael Juma <ismael@juma.me.uk>
andrey-klochkov-liftoff
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Aug 17, 2020
…#8451) A read from the end of the log interleaved with a concurrent write can result in reading data above the expected read limit. In particular, this would allow a read above the high watermark. The root of the problem is consecutive calls to `sizeInBytes` in `FileRecords.slice` which do not account for an increase in size due to a concurrent write. This patch fixes the problem by using a single call to `sizeInBytes` and caching the result. Reviewers: Ismael Juma <ismael@juma.me.uk>
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A read from the end of the log interleaved with a concurrent write can result in reading data above the expected limit. In particular, this would allow a read above the high watermark. The root of the problem is consecutive calls to
sizeInBytesinFileRecords.slicewhich do not account for an increase in size. This patch fixes the problem by using a single call tosizeInBytesand caching the result.Committer Checklist (excluded from commit message)