From: Michael Paquier Date: Tue, 30 Sep 2025 00:02:09 +0000 (+0900) Subject: injection_points: Add proper locking when reporting fixed-variable stats X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3cc689f833b1c9c5b52f1fe07c0e0fd817e23c8b;p=thirdparty%2Fpostgresql.git injection_points: Add proper locking when reporting fixed-variable stats Contrary to its siblings for the archiver, the bgwriter and the checkpointer stats, pgstat_report_inj_fixed() can be called concurrently. This was causing an assertion failure, while messing up with the stats. This code is aimed at being a template for extension developers, so it is not a critical issue, but let's be correct. This module has also been useful for some benchmarking, at least for me, and that was how I have discovered this issue. Oversight in f68cd847fa40. Author: Michael Paquier Reviewed-by: Bertrand Drouvot Reviewed-by: Chao Li Reviewed-by: wenhui qiu Discussion: https://postgr.es/m/aNnXbAXHPFUWPIz2@paquier.xyz Backpatch-through: 18 --- diff --git a/src/test/modules/injection_points/injection_stats_fixed.c b/src/test/modules/injection_points/injection_stats_fixed.c index bc54c79d190..74c35fcbfa7 100644 --- a/src/test/modules/injection_points/injection_stats_fixed.c +++ b/src/test/modules/injection_points/injection_stats_fixed.c @@ -152,6 +152,8 @@ pgstat_report_inj_fixed(uint32 numattach, stats_shmem = pgstat_get_custom_shmem_data(PGSTAT_KIND_INJECTION_FIXED); + LWLockAcquire(&stats_shmem->lock, LW_EXCLUSIVE); + pgstat_begin_changecount_write(&stats_shmem->changecount); stats_shmem->stats.numattach += numattach; stats_shmem->stats.numdetach += numdetach; @@ -159,6 +161,8 @@ pgstat_report_inj_fixed(uint32 numattach, stats_shmem->stats.numcached += numcached; stats_shmem->stats.numloaded += numloaded; pgstat_end_changecount_write(&stats_shmem->changecount); + + LWLockRelease(&stats_shmem->lock); } /*