Commit 8723ec22 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
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selftests/bpf: Fix rcu_read_lock test with new MEM_RCU semantics 



Add MEM_RCU pointer null checking for related tests. Also
modified task_acquire test so it takes a rcu ptr 'ptr' where
'ptr = rcu_ptr->rcu_field'.

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221203184607.478314-1-yhs@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent fca1aa75

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

+45 −10
Original line number Diff line number Diff line
@@ -23,13 +23,14 @@ struct bpf_key *bpf_lookup_user_key(__u32 serial, __u64 flags) __ksym; 
void bpf_key_put(struct bpf_key *key) __ksym;

void bpf_rcu_read_lock(void) __ksym;

void bpf_rcu_read_unlock(void) __ksym;

struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym;

struct task_struct *bpf_task_acquire_not_zero(struct task_struct *p) __ksym;

void bpf_task_release(struct task_struct *p) __ksym;



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

int get_cgroup_id(void *ctx)

{

	struct task_struct *task;

	struct css_set *cgroups;



	task = bpf_get_current_task_btf();

	if (task->pid != target_pid)
@@ -37,7 +38,11 @@ int get_cgroup_id(void *ctx) 


	/* simulate bpf_get_current_cgroup_id() helper */

	bpf_rcu_read_lock();

	cgroup_id = task->cgroups->dfl_cgrp->kn->id;

	cgroups = task->cgroups;

	if (!cgroups)

		goto unlock;

	cgroup_id = cgroups->dfl_cgrp->kn->id;

unlock:

	bpf_rcu_read_unlock();

	return 0;

}
@@ -56,6 +61,8 @@ int task_succ(void *ctx) 
	bpf_rcu_read_lock();

	/* region including helper using rcu ptr real_parent */

	real_parent = task->real_parent;

	if (!real_parent)

		goto out;

	ptr = bpf_task_storage_get(&map_a, real_parent, &init_val,

				   BPF_LOCAL_STORAGE_GET_F_CREATE);

	if (!ptr)
@@ -92,7 +99,10 @@ int two_regions(void *ctx) 
	bpf_rcu_read_unlock();

	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();

	return 0;

}
@@ -105,7 +115,10 @@ int non_sleepable_1(void *ctx) 
	task = bpf_get_current_task_btf();

	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();

	return 0;

}
@@ -121,7 +134,10 @@ int non_sleepable_2(void *ctx) 


	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();

	return 0;

}
@@ -129,16 +145,28 @@ int non_sleepable_2(void *ctx) 
SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep")

int task_acquire(void *ctx)

{

	struct task_struct *task, *real_parent;

	struct task_struct *task, *real_parent, *gparent;



	task = bpf_get_current_task_btf();

	bpf_rcu_read_lock();

	real_parent = task->real_parent;

	if (!real_parent)

		goto out;



	/* rcu_ptr->rcu_field */

	gparent = real_parent->real_parent;

	if (!gparent)

		goto out;



	/* acquire a reference which can be used outside rcu read lock region */

	real_parent = bpf_task_acquire(real_parent);

	gparent = bpf_task_acquire_not_zero(gparent);

	if (!gparent)

		goto out;



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

	bpf_task_release(gparent);

out:

	bpf_rcu_read_unlock();

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

	bpf_task_release(real_parent);

	return 0;

}
@@ -181,9 +209,12 @@ int non_sleepable_rcu_mismatch(void *ctx) 
	/* non-sleepable: missing bpf_rcu_read_unlock() in one path */

	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);

	if (real_parent)

		bpf_rcu_read_unlock();

out:

	return 0;

}
@@ -199,16 +230,17 @@ int inproper_sleepable_helper(void *ctx) 
	/* sleepable helper in rcu read lock region */

	bpf_rcu_read_lock();

	real_parent = task->real_parent;

	if (!real_parent)

		goto out;

	regs = (struct pt_regs *)bpf_task_pt_regs(real_parent);

	if (!regs) {

		bpf_rcu_read_unlock();

		return 0;

	}

	if (!regs)

		goto out;



	ptr = (void *)PT_REGS_IP(regs);

	(void)bpf_copy_from_user_task(&value, sizeof(uint32_t), ptr, task, 0);

	user_data = value;

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

out:

	bpf_rcu_read_unlock();

	return 0;

}
@@ -239,7 +271,10 @@ int nested_rcu_region(void *ctx) 
	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;