From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <ast@kernel.org>, <daniel@iogearbox.net>
Cc: <andrii@kernel.org>, <kernel-team@fb.com>, Tejun Heo <tj@kernel.org>
Subject: [PATCH bpf-next 08/17] bpf: ensure that r0 is marked scratched after any function call
Date: Thu, 2 Mar 2023 15:50:06 -0800 [thread overview]
Message-ID: <20230302235015.2044271-9-andrii@kernel.org> (raw)
In-Reply-To: <20230302235015.2044271-1-andrii@kernel.org>
r0 is important (unless called function is void-returning, but that's
taken care of by print_verifier_state() anyways) in verifier logs.
Currently for helpers we seem to print it in verifier log, but for
kfuncs we don't.
Instead of figuring out where in the maze of code we accidentally set r0
as scratched for helpers and why we don't do that for kfuncs, just
enforce that after any function call r0 is marked as scratched.
Also, perhaps, we should reconsider "scratched" terminology, as it's
mightily confusing. "Touched" would seem more appropriate. But I left
that for follow ups for now.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
kernel/bpf/verifier.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 666e416dc8a2..0004c9f3737f 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -15001,6 +15001,8 @@ static int do_check(struct bpf_verifier_env *env)
err = check_helper_call(env, insn, &env->insn_idx);
if (err)
return err;
+
+ mark_reg_scratched(env, BPF_REG_0);
} else if (opcode == BPF_JA) {
if (BPF_SRC(insn->code) != BPF_K ||
insn->imm != 0 ||
--
2.30.2
next prev parent reply other threads:[~2023-03-02 23:50 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-02 23:49 [PATCH bpf-next 00/17] BPF open-coded iterators Andrii Nakryiko
2023-03-02 23:49 ` [PATCH bpf-next 01/17] bpf: improve stack slot state printing Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 02/17] bpf: improve regsafe() checks for PTR_TO_{MEM,BUF,TP_BUFFER} Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 03/17] selftests/bpf: enhance align selftest's expected log matching Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 04/17] bpf: honor env->test_state_freq flag in is_state_visited() Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 05/17] selftests/bpf: adjust log_fixup's buffer size for proper truncation Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 06/17] bpf: clean up visit_insn()'s instruction processing Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 07/17] bpf: fix visit_insn()'s detection of BPF_FUNC_timer_set_callback helper Andrii Nakryiko
2023-03-02 23:50 ` Andrii Nakryiko [this message]
2023-03-02 23:50 ` [PATCH bpf-next 09/17] bpf: move kfunc_call_arg_meta higher in the file Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 10/17] bpf: mark PTR_TO_MEM as non-null register type Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 11/17] bpf: generalize dynptr_get_spi to be usable for iters Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 12/17] bpf: add support for fixed-size memory pointer returns for kfuncs Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 13/17] bpf: add support for open-coded iterator loops Andrii Nakryiko
2023-03-04 20:02 ` Alexei Starovoitov
2023-03-04 23:27 ` Andrii Nakryiko
2023-03-05 23:46 ` Alexei Starovoitov
2023-03-07 21:54 ` Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 14/17] bpf: implement number iterator Andrii Nakryiko
2023-03-04 20:21 ` Alexei Starovoitov
2023-03-04 23:27 ` Andrii Nakryiko
2023-03-05 23:49 ` Alexei Starovoitov
2023-03-02 23:50 ` [PATCH bpf-next 15/17] selftests/bpf: add bpf_for_each(), bpf_for(), and bpf_repeat() macros Andrii Nakryiko
2023-03-04 20:34 ` Alexei Starovoitov
2023-03-04 23:28 ` Andrii Nakryiko
2023-03-06 0:12 ` Alexei Starovoitov
2023-03-07 21:54 ` Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 16/17] selftests/bpf: add iterators tests Andrii Nakryiko
2023-03-04 20:39 ` Alexei Starovoitov
2023-03-04 23:29 ` Andrii Nakryiko
2023-03-06 0:14 ` Alexei Starovoitov
2023-03-04 21:09 ` Jiri Olsa
2023-03-04 23:29 ` Andrii Nakryiko
2023-03-02 23:50 ` [PATCH bpf-next 17/17] selftests/bpf: add number iterator tests Andrii Nakryiko
2023-03-04 19:30 ` [PATCH bpf-next 00/17] BPF open-coded iterators patchwork-bot+netdevbpf
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