On Wed, 4 Feb 2026 17:20:49 +0800
Chao Li <li.evan.chao@gmail.com> wrote:
> 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
usedhere.
>
> 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_upgraderuns. More generally, I don’t see a reason to free an object itself without also freeing the memory owned by
itsmembers.
As far as I know, AllocSlruSegState() and FreeSlruWrite() are not called
repeatedly in a loop, and the amount of memory involved is small, so the
impact of the leak seems limited. That said, I agree that it is better to
also free the memory owned by the struct members.
Regards,
Yugo Nagata
>
> 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
associatedwith SlruSegState.
>
> See the attached patch.
>
> Best regards,
> --
> Chao Li (Evan)
> HighGo Software Co., Ltd.
> https://www.highgo.com/
>
>
>
>
--
Yugo Nagata <nagata@sraoss.co.jp>
