Hi Hackers, This comes from a previous review and has been on my to-do list for a while.
Since src/bin/pg_upgrade/slru_io.c includes postgres_fe.h, it is frontend code,
so backend memory contexts are not used here.
In the current code:
```
void
FreeSlruWrite(SlruSegState *state)
{
Assert(state->writing);
SlruFlush(state);
if (state->fd != -1)
close(state->fd);
pg_free(state);
}
```
the SlruSegState itself is freed, but state->dir and state->fn are not, which
results in a memory leak during pg_upgrade runs. More generally, I don’t see a
reason to free an object itself without also freeing the memory owned by its
members.
While looking at this, I also noticed that state->dir is allocated using
pstrdup(). To better align with frontend conventions, the patch switches this
to pg_strdup() and introduces a common cleanup helper to free all resources
associated with SlruSegState.
See the attached patch.
Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/
v1-0001-pg_upgrade-fix-memory-leak-in-SLRU-I-O-code.patch
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