Commit 950b3477 authored by Daniel Müller's avatar Daniel Müller Committed by Andrii Nakryiko
Browse files

selftests/bpf: Add type match test against kernel's task_struct 



This change extends the existing core_reloc/kernel test to include a
type match check of a local task_struct against the kernel's definition
-- which we assume to succeed.

Signed-off-by: default avatarDaniel Müller <deso@posteo.net>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220628160127.607834-11-deso@posteo.net
parent 537905c4

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

+1 −0
Original line number Diff line number Diff line
@@ -555,6 +555,7 @@ static const struct core_reloc_test_case test_cases[] = { 
			.valid = { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, },

			.comm = "test_progs",

			.comm_len = sizeof("test_progs"),

			.local_task_struct_matches = true,

		},

		.output_len = sizeof(struct core_reloc_kernel_output),

		.raw_tp_name = "sys_enter",

tools/testing/selftests/bpf/progs/core_reloc_types.h

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ struct core_reloc_kernel_output { 
	int valid[10];

	char comm[sizeof("test_progs")];

	int comm_len;

	bool local_task_struct_matches;

};



/*

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

+19 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ struct core_reloc_kernel_output { 
	/* we have test_progs[-flavor], so cut flavor part */

	char comm[sizeof("test_progs")];

	int comm_len;

	bool local_task_struct_matches;

};



struct task_struct {
@@ -30,11 +31,25 @@ struct task_struct { 
	struct task_struct *group_leader;

};



struct mm_struct___wrong {

    int abc_whatever_should_not_exist;

};



struct task_struct___local {

    int pid;

    struct mm_struct___wrong *mm;

};



#define CORE_READ(dst, src) bpf_core_read(dst, sizeof(*(dst)), src)



SEC("raw_tracepoint/sys_enter")

int test_core_kernel(void *ctx)

{

	/* Support for the BPF_TYPE_MATCHES argument to the

	 * __builtin_preserve_type_info builtin was added at some point during

	 * development of clang 15 and it's what we require for this test.

	 */

#if __has_builtin(__builtin_preserve_type_info) && __clang_major__ >= 15

	struct task_struct *task = (void *)bpf_get_current_task();

	struct core_reloc_kernel_output *out = (void *)&data.out;

	uint64_t pid_tgid = bpf_get_current_pid_tgid();
@@ -93,6 +108,10 @@ int test_core_kernel(void *ctx) 
		group_leader, group_leader, group_leader, group_leader,

		comm);



	out->local_task_struct_matches = bpf_core_type_matches(struct task_struct___local);

#else

	data.skip = true;

#endif

	return 0;

}