MDEV-35717: UBSAN: runtime error: applying zero offset to null pointer in my_strnncoll_utf8mb3_general1400_as_ci#4910
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…r in `my_strnncoll_utf8mb3_general1400_as_ci`
Problem:
UBSAN reports runtime errors in string comparision functions when
pointer arithmetic is done without checking NULL.
Fix:
- Add debug asserts in `strnncoll` function to catch NULL pointers.
- Define a new function `streq_safe` as a replacement for `streq`,
capable of handling NULL pointers. Replace `streq` with `streq_safe`
at multiple call sites, identified by the debug asserts.
- Add empty identifier checks in `is_infoschema_db` and
`is_perfschema_db` before calling the deep character-set based
comparision.
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abarkov
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Apr 15, 2026
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The patch is OK to push. Thanks.
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fixes MDEV-35717
Problem:
UBSAN reports runtime errors in string comparision functions where pointer arithmetic is done without checking NULL.
my_strnncoll_utf8mb3_general1400_as_ciFix:
strnncollfunction to catch NULL pointers.streq_safeas a replacement forstreq, capable of handling NULL pointers. Replacestreqwithstreq_safeat multiple call sites, identified by the debug asserts.is_infoschema_dbandis_perfschema_dbbefore calling the deep character-set based comparison.