From cf49ec5705a6fb635ac9c2626f9ac7a39344b1f5 Mon Sep 17 00:00:00 2001 From: Puranjay Mohan Date: Mon, 17 Nov 2025 20:04:10 +0000 Subject: [PATCH] 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: Puranjay Mohan Acked-by: Eduard Zingerman Link: https://lore.kernel.org/r/20251117200411.25563-3-puranjay@kernel.org Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/rcu_read_lock.c | 2 + .../selftests/bpf/progs/rcu_read_lock.c | 40 +++++++++++++++++++ 2 files changed, 42 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c b/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c index 451a5d9ff4cb6..246eb259c08a1 100644 --- a/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c +++ b/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c @@ -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", diff --git a/tools/testing/selftests/bpf/progs/rcu_read_lock.c b/tools/testing/selftests/bpf/progs/rcu_read_lock.c index 3a868a1993492..d70c28824bbe3 100644 --- a/tools/testing/selftests/bpf/progs/rcu_read_lock.c +++ b/tools/testing/selftests/bpf/progs/rcu_read_lock.c @@ -278,6 +278,46 @@ out: 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) { -- 2.47.3