Instead of simply calling free() in expr->smp->arg_p in certain cases properly free the sample using release_sample_expr().
Given the following example configuration: frontend foo bind *:8080 mode http http-request set-var(txn.foo) str(bar) acl is_match str(foo),strcmp(txn.hash) -m bool Running a configuration check within valgrind reports: ==31371== 160 (48 direct, 112 indirect) bytes in 1 blocks are definitely lost in loss record 35 of 45 ==31371== at 0x4C2FB55: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==31371== by 0x4C3832: sample_parse_expr (sample.c:876) ==31371== by 0x56B3E0: parse_acl_expr (acl.c:319) ==31371== by 0x56BA4F: parse_acl (acl.c:697) ==31371== by 0x48D225: cfg_parse_listen (cfgparse-listen.c:816) ==31371== by 0x4797C3: readcfgfile (cfgparse.c:2167) ==31371== by 0x5293ED: init (haproxy.c:2021) ==31371== by 0x41F382: main (haproxy.c:3126) After this patch this leak is reduced. It will be fully removed in a follow up patch: ==32503== 32 bytes in 1 blocks are definitely lost in loss record 20 of 43 ==32503== at 0x4C2FB55: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==32503== by 0x4C39B5: sample_parse_expr (sample.c:982) ==32503== by 0x56B410: parse_acl_expr (acl.c:319) ==32503== by 0x56BA7F: parse_acl (acl.c:697) ==32503== by 0x48D225: cfg_parse_listen (cfgparse-listen.c:816) ==32503== by 0x4797C3: readcfgfile (cfgparse.c:2167) ==32503== by 0x52943D: init (haproxy.c:2021) ==32503== by 0x41F382: main (haproxy.c:3133) This is a fairly minor leak that can only be observed if ACLs need to be freed, which is not something that should occur during normal processing and most likely only during shut down. Thus no backport should be needed. --- src/acl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/acl.c b/src/acl.c index 5fea5dcc2..333da22c9 100644 --- a/src/acl.c +++ b/src/acl.c @@ -117,8 +117,8 @@ static struct acl_expr *prune_acl_expr(struct acl_expr *expr) } } - if (expr->smp->arg_p != empty_arg_list && !unresolved) - free(expr->smp->arg_p); + release_sample_expr(expr->smp); + return expr; } -- 2.27.0