Commit 9f3330aa authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Alexei Starovoitov
Browse files

selftests/bpf: test widening for iterating callbacks 



A test case to verify that imprecise scalars widening is applied to
callback entering state, when callback call is simulated repeatedly.

Signed-off-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20231121020701.26440-10-eddyz87@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent cafe2c21

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

+20 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ struct buf_context { 


struct num_context {

	__u64 i;

	__u64 j;

};



__u8 choice_arr[2] = { 0, 1 };
@@ -69,6 +70,25 @@ int unsafe_on_zero_iter(void *unused) 
	return choice_arr[loop_ctx.i];

}



static int widening_cb(__u32 idx, struct num_context *ctx)

{

	++ctx->i;

	return 0;

}



SEC("?raw_tp")

__success

int widening(void *unused)

{

	struct num_context loop_ctx = { .i = 0, .j = 1 };



	bpf_loop(100, widening_cb, &loop_ctx, 0);

	/* loop_ctx.j is not changed during callback iteration,

	 * verifier should not apply widening to it.

	 */

	return choice_arr[loop_ctx.j];

}



static int loop_detection_cb(__u32 idx, struct num_context *ctx)

{

	for (;;) {}