Commit f6ef5584 authored by Puranjay Mohan's avatar Puranjay Mohan Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add a test for ids=0 to verifier_scalar_ids test 



Test that two registers with their id=0 (unlinked) in the cached state
can be mapped to a single id (linked) in the current state.

Signed-off-by: default avatarPuranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260203165102.2302462-6-puranjay@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent b0388baf

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

+45 −0
Original line number Diff line number Diff line
@@ -715,6 +715,51 @@ __naked void ignore_unique_scalar_ids_old(void) 
	: __clobber_all);

}



/* Check that two registers with 0 scalar IDs in a verified state can be mapped

 * to the same scalar ID in current state.

 */

SEC("socket")

__success __log_level(2)

/* The states should be equivalent on reaching insn 12.

 */

__msg("12: safe")

__msg("processed 17 insns")

__flag(BPF_F_TEST_STATE_FREQ)

__naked void two_nil_old_ids_one_cur_id(void)

{

	asm volatile (

	/* Give unique scalar IDs to r{6,7} */

	"call %[bpf_ktime_get_ns];"

	"r0 &= 0xff;"

	"r6 = r0;"

	"r6 *= 1;"

	"call %[bpf_ktime_get_ns];"

	"r0 &= 0xff;"

	"r7 = r0;"

	"r7 *= 1;"

	"r0 = 0;"

	/* Maybe make r{6,7} IDs identical */

	"if r6 > r7 goto l0_%=;"

	"goto l1_%=;"

"l0_%=:"

	"r6 = r7;"

"l1_%=:"

	/* Mark r{6,7} precise.

	 * Get here in two states:

	 * - first:  r6{.id=0}, r7{.id=0} (cached state)

	 * - second: r6{.id=A}, r7{.id=A}

	 * Verifier considers such states equivalent.

	 * Thus "exit;" would be verified only once.

	 */

	"r2 = r10;"

	"r2 += r6;"

	"r2 += r7;"

	"exit;"

	:

	: __imm(bpf_ktime_get_ns)

	: __clobber_all);

}



/* Check that two different scalar IDs in a verified state can't be

 * mapped to the same scalar ID in current state.

 */