Commit e8699c4f authored by Kumar Kartikeya Dwivedi's avatar Kumar Kartikeya Dwivedi Committed by Alexei Starovoitov
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selftests/bpf: Add test for static subprog call in lock cs 



Add selftests for static subprog calls within bpf_spin_lock critical
section, and ensure we still reject global subprog calls. Also test the
case where a subprog call will unlock the caller's held lock, or the
caller will unlock a lock taken by a subprog call, ensuring correct
transfer of lock state across frames on exit.

Acked-by: default avatarYonghong Song <yonghong.song@linux.dev>
Acked-by: default avatarDavid Vernet <void@manifault.com>
Signed-off-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20240204222349.938118-3-memxor@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent a44b1334

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

+2 −0
Original line number Diff line number Diff line
@@ -48,6 +48,8 @@ static struct { 
	{ "lock_id_mismatch_innermapval_kptr", "bpf_spin_unlock of different lock" },

	{ "lock_id_mismatch_innermapval_global", "bpf_spin_unlock of different lock" },

	{ "lock_id_mismatch_innermapval_mapval", "bpf_spin_unlock of different lock" },

	{ "lock_global_subprog_call1", "global function calls are not allowed while holding a lock" },

	{ "lock_global_subprog_call2", "global function calls are not allowed while holding a lock" },

};



static int match_regex(const char *pattern, const char *string)

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

+65 −0
Original line number Diff line number Diff line
@@ -101,4 +101,69 @@ int bpf_spin_lock_test(struct __sk_buff *skb) 
err:

	return err;

}



struct bpf_spin_lock lockA __hidden SEC(".data.A");



__noinline

static int static_subprog(struct __sk_buff *ctx)

{

	volatile int ret = 0;



	if (ctx->protocol)

		return ret;

	return ret + ctx->len;

}



__noinline

static int static_subprog_lock(struct __sk_buff *ctx)

{

	volatile int ret = 0;



	ret = static_subprog(ctx);

	bpf_spin_lock(&lockA);

	return ret + ctx->len;

}



__noinline

static int static_subprog_unlock(struct __sk_buff *ctx)

{

	volatile int ret = 0;



	ret = static_subprog(ctx);

	bpf_spin_unlock(&lockA);

	return ret + ctx->len;

}



SEC("tc")

int lock_static_subprog_call(struct __sk_buff *ctx)

{

	int ret = 0;



	bpf_spin_lock(&lockA);

	if (ctx->mark == 42)

		ret = static_subprog(ctx);

	bpf_spin_unlock(&lockA);

	return ret;

}



SEC("tc")

int lock_static_subprog_lock(struct __sk_buff *ctx)

{

	int ret = 0;



	ret = static_subprog_lock(ctx);

	bpf_spin_unlock(&lockA);

	return ret;

}



SEC("tc")

int lock_static_subprog_unlock(struct __sk_buff *ctx)

{

	int ret = 0;



	bpf_spin_lock(&lockA);

	ret = static_subprog_unlock(ctx);

	return ret;

}



char _license[] SEC("license") = "GPL";

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

+44 −0
Original line number Diff line number Diff line
@@ -201,4 +201,48 @@ CHECK(innermapval_mapval, &iv->lock, &v->lock); 


#undef CHECK



__noinline

int global_subprog(struct __sk_buff *ctx)

{

	volatile int ret = 0;



	if (ctx->protocol)

		ret += ctx->protocol;

	return ret + ctx->mark;

}



__noinline

static int static_subprog_call_global(struct __sk_buff *ctx)

{

	volatile int ret = 0;



	if (ctx->protocol)

		return ret;

	return ret + ctx->len + global_subprog(ctx);

}



SEC("?tc")

int lock_global_subprog_call1(struct __sk_buff *ctx)

{

	int ret = 0;



	bpf_spin_lock(&lockA);

	if (ctx->mark == 42)

		ret = global_subprog(ctx);

	bpf_spin_unlock(&lockA);

	return ret;

}



SEC("?tc")

int lock_global_subprog_call2(struct __sk_buff *ctx)

{

	int ret = 0;



	bpf_spin_lock(&lockA);

	if (ctx->mark == 42)

		ret = static_subprog_call_global(ctx);

	bpf_spin_unlock(&lockA);

	return ret;

}



char _license[] SEC("license") = "GPL";