From: Eduard Zingerman <eddyz87@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org, andrii@kernel.org
Cc: daniel@iogearbox.net, martin.lau@linux.dev, kernel-team@fb.com,
yonghong.song@linux.dev, eddyz87@gmail.com, memxor@gmail.com
Subject: [PATCH bpf 06/10] selftests/bpf: precision of a NULL kfunc argument
Date: Fri, 4 Sep 2026 17:05:57 -0700 [thread overview]
Message-ID: <20260904-register-is-null-precise-fixes-v1-6-0f5a360ff15d@gmail.com> (raw)
In-Reply-To: <20260904-register-is-null-precise-fixes-v1-0-0f5a360ff15d@gmail.com>
Check that mark_chain_precision() is called for a NULL pointer passed
as a __nullable kfunc memory argument.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
.../selftests/bpf/progs/verifier_precision.c | 34 ++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/verifier_precision.c b/tools/testing/selftests/bpf/progs/verifier_precision.c
index fb7dfa1246ef..f4459561bf39 100644
--- a/tools/testing/selftests/bpf/progs/verifier_precision.c
+++ b/tools/testing/selftests/bpf/progs/verifier_precision.c
@@ -2,8 +2,10 @@
/* Copyright (C) 2023 SUSE LLC */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
+#include <stdbool.h>
#include "../../../include/linux/filter.h"
#include "bpf_misc.h"
+#include "bpf_kfuncs.h"
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
@@ -708,4 +710,36 @@ __naked int null_mem_arg_global_subprog(void)
: __clobber_all);
}
+/* Same as above, check that path with r3 == 0 does not prune the path with r3 != 0 */
+SEC("?tc")
+__flag(BPF_F_TEST_STATE_FREQ)
+__failure __msg("R3 type=scalar expected=fp")
+int null_kfunc_arg_dynptr_slice(struct __sk_buff *skb)
+{
+ struct bpf_dynptr ptr;
+
+ bpf_dynptr_from_skb(skb, 0, &ptr);
+ asm volatile (
+ "call %[bpf_get_prandom_u32];"
+ "r3 = 42;"
+ "if r0 > 42 goto 1f;"
+ "r3 = 0;"
+ "1:"
+ "r1 = %[ptr];"
+ "r2 = 0;"
+ "r4 = 8;"
+ "call %[bpf_dynptr_slice];"
+ :
+ : __imm_ptr(ptr),
+ __imm(bpf_get_prandom_u32),
+ __imm(bpf_dynptr_slice)
+ : __clobber_common);
+ return 0;
+}
+
+void __kfunc_btf_root(void)
+{
+ bpf_dynptr_slice(0, 0, 0, 0);
+}
+
char _license[] SEC("license") = "GPL";
--
2.55.0
next prev parent reply other threads:[~2026-09-05 0:06 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-05 0:05 [PATCH bpf 00/10] bpf: add missing precision propagation after bpf_register_is_null calls Eduard Zingerman
2026-09-05 0:05 ` [PATCH bpf 01/10] bpf: mark a NULL call argument precise Eduard Zingerman
2026-09-05 0:21 ` sashiko-bot
2026-09-05 0:05 ` [PATCH bpf 02/10] selftests/bpf: precision of a NULL helper argument Eduard Zingerman
2026-09-05 0:05 ` [PATCH bpf 03/10] bpf: mark a NULL memory argument of a call precise Eduard Zingerman
2026-09-05 0:23 ` sashiko-bot
2026-09-05 0:51 ` bot+bpf-ci
2026-09-05 0:05 ` [PATCH bpf 04/10] selftests/bpf: precision of a NULL global subprogram memory argument Eduard Zingerman
2026-09-05 0:51 ` bot+bpf-ci
2026-09-05 0:05 ` [PATCH bpf 05/10] bpf: mark a NULL kfunc argument precise Eduard Zingerman
2026-09-05 0:51 ` bot+bpf-ci
2026-09-05 0:05 ` Eduard Zingerman [this message]
2026-09-05 0:05 ` [PATCH bpf 07/10] bpf: mark a NULL BTF_ID argument of a global subprogram precise Eduard Zingerman
2026-09-05 0:19 ` sashiko-bot
2026-09-05 0:05 ` [PATCH bpf 08/10] selftests/bpf: precision of a NULL global subprogram BTF_ID argument Eduard Zingerman
2026-09-05 0:06 ` [PATCH bpf 09/10] bpf: propagate mark_chain_precision() errors out of loop_flag_is_zero() Eduard Zingerman
2026-09-05 0:06 ` [PATCH bpf 10/10] bpf: use mark_arg_precision() in check_mem_size_reg() Eduard Zingerman
2026-09-05 0:51 ` bot+bpf-ci
2026-09-05 1:20 ` [PATCH bpf 00/10] bpf: add missing precision propagation after bpf_register_is_null calls patchwork-bot+netdevbpf
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