From: Eduard Zingerman <eddyz87@gmail.com>
To: Kumar Kartikeya Dwivedi <memxor@gmail.com>, bpf@vger.kernel.org
Cc: kkd@meta.com, Manu Bretelle <chantra@meta.com>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@kernel.org>,
kernel-team@fb.com
Subject: Re: [PATCH bpf v2 1/2] bpf: Suppress warning for non-zero off raw_tp arg NULL check
Date: Thu, 05 Dec 2024 16:00:21 -0800 [thread overview]
Message-ID: <e991f994d9e24b146526b57ae038d7abd5fa1239.camel@gmail.com> (raw)
In-Reply-To: <20241205223152.2434683-2-memxor@gmail.com>
On Thu, 2024-12-05 at 14:31 -0800, Kumar Kartikeya Dwivedi wrote:
[...]
> Fixes: cb4158ce8ec8 ("bpf: Mark raw_tp arguments with PTR_MAYBE_NULL")
> Reported-by: Manu Bretelle <chantra@meta.com>
> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
> ---
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
I think this should work.
Although, I'm not sure if we should delay generic fix and do this in two steps.
> kernel/bpf/verifier.c | 38 ++++++++++++++++++++++++++++++--------
> 1 file changed, 30 insertions(+), 8 deletions(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 2fd35465d650..dea92cac2522 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -15340,7 +15340,8 @@ static int reg_set_min_max(struct bpf_verifier_env *env,
> return err;
> }
>
> -static void mark_ptr_or_null_reg(struct bpf_func_state *state,
> +static void mark_ptr_or_null_reg(struct bpf_verifier_env *env,
> + struct bpf_func_state *state,
> struct bpf_reg_state *reg, u32 id,
> bool is_null)
> {
> @@ -15357,8 +15358,8 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state,
> */
> if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || !tnum_equals_const(reg->var_off, 0)))
> return;
> - if (!(type_is_ptr_alloc_obj(reg->type) || type_is_non_owning_ref(reg->type)) &&
> - WARN_ON_ONCE(reg->off))
> + if (!(type_is_ptr_alloc_obj(reg->type) || type_is_non_owning_ref(reg->type) ||
> + mask_raw_tp_reg_cond(env, reg)) && WARN_ON_ONCE(reg->off))
Nit: the condition is a bit hard to read, maybe rewrite it as follows:
if (!type_is_ptr_alloc_obj(reg->type) &&
!type_is_non_owning_ref(reg->type) &&
!mask_raw_tp_reg_cond(env, reg) &&
WARN_ON_ONCE(reg->off))
return;
?
> return;
>
> if (is_null) {
[...]
next prev parent reply other threads:[~2024-12-06 0:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-05 22:31 [PATCH bpf v2 0/2] Fix for raw_tp PTR_MAYBE_NULL unmarking Kumar Kartikeya Dwivedi
2024-12-05 22:31 ` [PATCH bpf v2 1/2] bpf: Suppress warning for non-zero off raw_tp arg NULL check Kumar Kartikeya Dwivedi
2024-12-06 0:00 ` Eduard Zingerman [this message]
2024-12-05 22:31 ` [PATCH bpf v2 2/2] selftests/bpf: Add raw_tp tests for PTR_MAYBE_NULL marking Kumar Kartikeya Dwivedi
2024-12-06 0:08 ` Eduard Zingerman
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