Fix crash when reading stats file at startup with fixed-sized kinds pgstat_read_statsfile() has never checked that the kind of a hash entry is variable-sized. Since 44539786b829, that has begun tracking which hash table a kind ID should use, it is possible to finish with a NULL pointer dereference for a PGSTAT_FILE_ENTRY_HASH. Fixed-sized stats kinds have no hash table and no DSA area, hence their dsa references in pgStatLocal.kind_hash[] are NULL.
This case can occur when reading statistics files if the same kind ID is reused across server restarts, with shared_preload_libraries loading different stats kind information each time: stats written with a set of PGSTAT_FILE_ENTRY_HASH, then read back with the same kind ID pointing to a custom fixed-sized kind info. Oversight in 44539786b829. Reported-by: Zsolt Parragi <[email protected]> Author: Sami Imseih <[email protected]> Author: Zsolt Parragi <[email protected]> Discussion: https://postgr.es/m/CAN4CZFMxuOOuYV14+i3YcPG-16q02eBtSVa82J111=zndws...@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/0d110901f0ef362fcf24b07357c20745f971c602 Modified Files -------------- src/backend/utils/activity/pgstat.c | 8 ++++++++ 1 file changed, 8 insertions(+)
