[Backport release-2.23] Fix segfaults in WebP queries ran in parallel. (#5065) #5121
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The WebpFilter calls `WriterTile::set_max_tile_chunk_size` to override the maximum tile chunk size in an attempt to avoid further chunking data within each tile, but because `WriterTile::max_tile_chunk_size_` is static this doesn't work as intended when we're running multiple WebP queries across threads. It's possible for one thread to override this value while it's being used by another running query and this results in incorrect chunking for WebP data, potentially causing segfaults from libwebp reaching out of memory bounds. The WebP library was reaching out of bounds because after another thread overrides `max_tile_chunk_size_` we don't account for the smaller chunk's dimensions when calling WebP APIs and still pass in the same height, width, and row stride to [WebP API calls](https://github.com/TileDB-Inc/TileDB/blob/dev/tiledb/sm/filter/webp_filter.cc#L144). This PR removes the use of `WriterTile::set_max_tile_chunk_size` and updates `FilterPipeline::use_tile_chunking` to return `false` for WebP, which IIUC should have the behavior that was initially intended and fixes segfaults seen on REST. [SC-48697](https://app.shortcut.com/tiledb-inc/story/48697/rest-segfaults-running-webp-multiple-queries) Limitations: If a WebP array exists that was impacted by this during ingestion and it did not produce a segfault, that array will still be read back using chunking. AFAICT there is no risk of segfault for this case since the decoding APIs in WebP do not depend on the caller to specify buffer dimensions, instead WebP will decode and provides to the caller the width and height of the decoded image. On the next write to the array there will be no error or risk of segfault and the new tiles will not use chunking moving forward for reads or writes. --- TYPE: BUG DESC: Fix segfaults in WebP queries ran in parallel.
teo-tsirpanis
approved these changes
Jun 19, 2024
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Backport 47dde51 from #5065.
TYPE: BUG
DESC: Fix segfaults in WebP queries ran in parallel.