selftests: bpf: trigger arena list_del() bug.

puranjaymohan · puranjaymohan · commit 564f013f4f77 · 2025-10-17T18:56:57.000Z
Comment out the bpf_free() from arena_list_del() so the nodes are removed
by list_del() but the memory is not freed, this will trigger a bug showing
that list_del is doesn't remove nodes and just poisons the next and pprev
pointers.

Signed-off-by: Puranjay Mohan &lt;puranjay@kernel.org&gt;
diff --git a/tools/testing/selftests/bpf/progs/arena_list.c b/tools/testing/selftests/bpf/progs/arena_list.c
@@ -76,7 +76,7 @@ int arena_list_del(void *ctx)
 		sum += n->value;
 		arena_sum += n->value;
 		list_del(&n->node);
-		bpf_free(n);
+		//bpf_free(n);
 	}
 	list_sum = sum;
 #else

Original file line number	Diff line number	Diff line change
`@@ -76,7 +76,7 @@ int arena_list_del(void *ctx)`
`76`	`76`	`sum += n->value;`
`77`	`77`	`arena_sum += n->value;`
`78`	`78`	`list_del(&n->node);`
`79`		`- bpf_free(n);`
	`79`	`+ //bpf_free(n);`
`80`	`80`	`}`
`81`	`81`	`list_sum = sum;`
`82`	`82`	`#else`