Commit cf49ec57 authored by Puranjay Mohan's avatar Puranjay Mohan Committed by Alexei Starovoitov
Browse files

selftests: bpf: Add tests for unbalanced rcu_read_lock 



As verifier now supports nested rcu critical sections, add new test
cases to make sure unbalanced usage of rcu_read_lock()/unlock() is
rejected.

Signed-off-by: default avatarPuranjay Mohan <puranjay@kernel.org>
Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251117200411.25563-3-puranjay@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 4167096c

tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c

+2 −0
Original line number Diff line number Diff line
@@ -79,6 +79,8 @@ static const char * const inproper_region_tests[] = { 
	"non_sleepable_rcu_mismatch",

	"inproper_sleepable_helper",

	"inproper_sleepable_kfunc",

	"nested_rcu_region_unbalanced_1",

	"nested_rcu_region_unbalanced_2",

	"rcu_read_lock_global_subprog_lock",

	"rcu_read_lock_global_subprog_unlock",

	"rcu_read_lock_sleepable_helper_global_subprog",

tools/testing/selftests/bpf/progs/rcu_read_lock.c

+40 −0
Original line number Diff line number Diff line
@@ -278,6 +278,46 @@ int nested_rcu_region(void *ctx) 
	return 0;

}



SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep")

int nested_rcu_region_unbalanced_1(void *ctx)

{

	struct task_struct *task, *real_parent;



	/* nested rcu read lock regions */

	task = bpf_get_current_task_btf();

	bpf_rcu_read_lock();

	bpf_rcu_read_lock();

	real_parent = task->real_parent;

	if (!real_parent)

		goto out;

	(void)bpf_task_storage_get(&map_a, real_parent, 0, 0);

out:

	bpf_rcu_read_unlock();

	bpf_rcu_read_unlock();

	bpf_rcu_read_unlock();

	return 0;

}



SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep")

int nested_rcu_region_unbalanced_2(void *ctx)

{

	struct task_struct *task, *real_parent;



	/* nested rcu read lock regions */

	task = bpf_get_current_task_btf();

	bpf_rcu_read_lock();

	bpf_rcu_read_lock();

	bpf_rcu_read_lock();

	real_parent = task->real_parent;

	if (!real_parent)

		goto out;

	(void)bpf_task_storage_get(&map_a, real_parent, 0, 0);

out:

	bpf_rcu_read_unlock();

	bpf_rcu_read_unlock();

	return 0;

}



SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")

int task_trusted_non_rcuptr(void *ctx)

{