Add task kptr tests that keep RCU protection active after a spin or RCU unlock when preemption or IRQs remain disabled.
Also test the reverse order with explicit RCU. Verify that task kptrs are rejected after leaving the final preemption-disabled or IRQ-disabled region. Signed-off-by: Ning Ding <[email protected]> --- .../selftests/bpf/prog_tests/task_kfunc.c | 6 + .../selftests/bpf/progs/task_kfunc_common.h | 2 + .../selftests/bpf/progs/task_kfunc_failure.c | 49 ++++++ .../selftests/bpf/progs/task_kfunc_success.c | 147 ++++++++++++++++++ 4 files changed, 204 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/task_kfunc.c b/tools/testing/selftests/bpf/prog_tests/task_kfunc.c index fbd7855712c1a..30d403028f984 100644 --- a/tools/testing/selftests/bpf/prog_tests/task_kfunc.c +++ b/tools/testing/selftests/bpf/prog_tests/task_kfunc.c @@ -178,6 +178,12 @@ static const char * const success_tests[] = { "task_kfunc_acquire_trusted_walked", "task_kfunc_acquire_after_spin_unlock_non_sleepable", "task_kfunc_acquire_after_spin_unlock_explicit_rcu", + "task_kfunc_acquire_after_spin_unlock_preempt_disabled", + "task_kfunc_acquire_after_spin_unlock_irq_disabled", + "task_kfunc_acquire_after_rcu_unlock_preempt_disabled", + "task_kfunc_acquire_after_rcu_unlock_irq_disabled", + "task_kfunc_acquire_after_preempt_enable_explicit_rcu", + "task_kfunc_acquire_after_irq_restore_explicit_rcu", "test_task_kfunc_flavor_relo", "test_task_kfunc_flavor_relo_not_found", }; diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_common.h b/tools/testing/selftests/bpf/progs/task_kfunc_common.h index 052c9d0e3e2a8..a0c599b58c290 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_common.h +++ b/tools/testing/selftests/bpf/progs/task_kfunc_common.h @@ -38,6 +38,8 @@ struct task_struct *bpf_task_from_pid(s32 pid) __ksym; struct task_struct *bpf_task_from_vpid(s32 vpid) __ksym; void bpf_rcu_read_lock(void) __ksym; void bpf_rcu_read_unlock(void) __ksym; +void bpf_local_irq_save(unsigned long *flags) __weak __ksym; +void bpf_local_irq_restore(unsigned long *flags) __weak __ksym; static inline struct __tasks_kfunc_map_value *tasks_kfunc_map_value_lookup(struct task_struct *p) { diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c index c0e7216b34193..f96b0c13ed1a5 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c +++ b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c @@ -402,3 +402,52 @@ int BPF_PROG(task_kfunc_acquire_after_final_spin_unlock) bpf_task_release(acquired); return 0; } + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +__failure __msg("R1 must be a rcu pointer") +int BPF_PROG(task_kfunc_acquire_after_preempt_enable) +{ + struct task_kptr_lock_value *v; + struct task_struct *task, *acquired; + int key = 0; + + v = bpf_map_lookup_elem(&task_kptr_lock_map, &key); + if (!v) + return 0; + + bpf_preempt_disable(); + task = v->task; + bpf_preempt_enable(); + if (!task) + return 0; + + acquired = bpf_task_acquire(task); + if (acquired) + bpf_task_release(acquired); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +__failure __msg("R1 must be a rcu pointer") +int BPF_PROG(task_kfunc_acquire_after_irq_restore) +{ + struct task_kptr_lock_value *v; + struct task_struct *task, *acquired; + unsigned long flags; + int key = 0; + + v = bpf_map_lookup_elem(&task_kptr_lock_map, &key); + if (!v) + return 0; + + bpf_local_irq_save(&flags); + task = v->task; + bpf_local_irq_restore(&flags); + if (!task) + return 0; + + acquired = bpf_task_acquire(task); + if (acquired) + bpf_task_release(acquired); + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_success.c b/tools/testing/selftests/bpf/progs/task_kfunc_success.c index 2bab7634c9dfd..6545b124dee14 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_success.c +++ b/tools/testing/selftests/bpf/progs/task_kfunc_success.c @@ -414,6 +414,153 @@ int BPF_PROG(task_kfunc_acquire_after_spin_unlock_explicit_rcu) return 0; } +SEC("fentry.s/" SYS_PREFIX "sys_getpgid") +int BPF_PROG(task_kfunc_acquire_after_spin_unlock_preempt_disabled) +{ + struct task_kptr_lock_value *v; + struct task_struct *task, *acquired; + int key = 0; + + v = bpf_map_lookup_elem(&task_kptr_lock_map, &key); + if (!v) + return 0; + + bpf_preempt_disable(); + bpf_spin_lock(&v->lock); + task = v->task; + bpf_spin_unlock(&v->lock); + if (task) { + acquired = bpf_task_acquire(task); + if (acquired) + bpf_task_release(acquired); + } + bpf_preempt_enable(); + return 0; +} + +SEC("fentry.s/" SYS_PREFIX "sys_getpgid") +int BPF_PROG(task_kfunc_acquire_after_spin_unlock_irq_disabled) +{ + struct task_kptr_lock_value *v; + struct task_struct *task, *acquired; + unsigned long flags; + int key = 0; + + v = bpf_map_lookup_elem(&task_kptr_lock_map, &key); + if (!v) + return 0; + + bpf_local_irq_save(&flags); + bpf_spin_lock(&v->lock); + task = v->task; + bpf_spin_unlock(&v->lock); + if (task) { + acquired = bpf_task_acquire(task); + if (acquired) + bpf_task_release(acquired); + } + bpf_local_irq_restore(&flags); + return 0; +} + +SEC("fentry.s/" SYS_PREFIX "sys_getpgid") +int BPF_PROG(task_kfunc_acquire_after_rcu_unlock_preempt_disabled) +{ + struct task_kptr_lock_value *v; + struct task_struct *task, *acquired; + int key = 0; + + v = bpf_map_lookup_elem(&task_kptr_lock_map, &key); + if (!v) + return 0; + + bpf_preempt_disable(); + bpf_rcu_read_lock(); + task = v->task; + bpf_rcu_read_unlock(); + if (task) { + acquired = bpf_task_acquire(task); + if (acquired) + bpf_task_release(acquired); + } + bpf_preempt_enable(); + return 0; +} + +SEC("fentry.s/" SYS_PREFIX "sys_getpgid") +int BPF_PROG(task_kfunc_acquire_after_rcu_unlock_irq_disabled) +{ + struct task_kptr_lock_value *v; + struct task_struct *task, *acquired; + unsigned long flags; + int key = 0; + + v = bpf_map_lookup_elem(&task_kptr_lock_map, &key); + if (!v) + return 0; + + bpf_local_irq_save(&flags); + bpf_rcu_read_lock(); + task = v->task; + bpf_rcu_read_unlock(); + if (task) { + acquired = bpf_task_acquire(task); + if (acquired) + bpf_task_release(acquired); + } + bpf_local_irq_restore(&flags); + return 0; +} + +SEC("fentry.s/" SYS_PREFIX "sys_getpgid") +int BPF_PROG(task_kfunc_acquire_after_preempt_enable_explicit_rcu) +{ + struct task_kptr_lock_value *v; + struct task_struct *task, *acquired; + int key = 0; + + v = bpf_map_lookup_elem(&task_kptr_lock_map, &key); + if (!v) + return 0; + + bpf_preempt_disable(); + task = v->task; + bpf_rcu_read_lock(); + bpf_preempt_enable(); + if (task) { + acquired = bpf_task_acquire(task); + if (acquired) + bpf_task_release(acquired); + } + bpf_rcu_read_unlock(); + return 0; +} + +SEC("fentry.s/" SYS_PREFIX "sys_getpgid") +int BPF_PROG(task_kfunc_acquire_after_irq_restore_explicit_rcu) +{ + struct task_kptr_lock_value *v; + struct task_struct *task, *acquired; + unsigned long flags; + int key = 0; + + v = bpf_map_lookup_elem(&task_kptr_lock_map, &key); + if (!v) + return 0; + + bpf_local_irq_save(&flags); + task = v->task; + bpf_rcu_read_lock(); + bpf_local_irq_restore(&flags); + if (task) { + acquired = bpf_task_acquire(task); + if (acquired) + bpf_task_release(acquired); + } + bpf_rcu_read_unlock(); + return 0; +} + SEC("syscall") int test_task_from_vpid_current(const void *ctx) { -- 2.43.0
