RFR: 8289697: buffer overflow in MTLVertexCache.m: MTLVertexCache_AddGlyphQuad [v2]

[Vladimir Kempik]

> Please review this simple patch. When running idea on jdk17 with asan I have found this buffer overflow.
> The code checks the cache for at least one free element, while placing 6 elements to the cache.
> The fix checks the presence of 6 free elements.

Vladimir Kempik has updated the pull request incrementally with one additional commit since the last revision:

  Add the check to one more place

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Changes:
  - all: https://git.openjdk.org/jdk/pull/9368/files
  - new: https://git.openjdk.org/jdk/pull/9368/files/35ed932e..88402dbe

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9368&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9368&range=00-01

  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/9368.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9368/head:pull/9368

PR: https://git.openjdk.org/jdk/pull/9368