SQLite

The sqlite3KeyInfoOfIndex() routine (here) can return a stale KeyInfo object in shared cache mode.

Scenario:

• Two open database connections (A and B) on the same cache
• The shared pIdx object is holding a KeyInfo object for A
• Connection A closes.
• Connection C opens, and by (bad) luck is allocated the same database connection pointer as A had.
• Connection C now tries to get a KeyInfo object for index pIdx but is handed the stale one from A. The KeyInfo object itself is ref-counted and so it is still live. But the KeyInfo points to CollSeq objects within the old A connection that are now dead and have been freed.

This problem appears to have been introduced by check-in [c80e229dd9c1230ab] on 2013-11-07, which first appeared in SQLite version 3.8.2.