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From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <martin.lau@kernel.org>,
	Dave Marchevsky <davemarchevsky@meta.com>
Subject: Re: [PATCH bpf-next v7 19/26] bpf: Permit NULL checking pointer with non-zero fixed offset
Date: Tue, 15 Nov 2022 22:27:33 +0530	[thread overview]
Message-ID: <20221115165733.t77fukodwgvv6g72@apollo> (raw)
In-Reply-To: <20221115062319.3hkphudyakopnqvb@macbook-pro-5.dhcp.thefacebook.com>

On Tue, Nov 15, 2022 at 11:53:19AM IST, Alexei Starovoitov wrote:
> On Tue, Nov 15, 2022 at 12:45:40AM +0530, Kumar Kartikeya Dwivedi wrote:
> >  	if (type_may_be_null(reg->type) && reg->id == id &&
> >  	    !WARN_ON_ONCE(!reg->id)) {
> > -		if (WARN_ON_ONCE(reg->smin_value || reg->smax_value ||
> > -				 !tnum_equals_const(reg->var_off, 0) ||
> > -				 reg->off)) {
> > +		if (reg->smin_value || reg->smax_value || !tnum_equals_const(reg->var_off, 0) || reg->off) {
> ....
> > +			if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || !tnum_equals_const(reg->var_off, 0)))
>
> That is too much copy-paste between two lines.
> Please combine the checks.

I have rewritten it like this:

if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || !tnum_equals_const(reg->var_off, 0))) ‣a: reg->var_off ‣b: 0 ‣: int
	  return;
if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL) && WARN_ON_ONCE(reg->off)) ‣: int
	  return;

I prefer to keep the WARN, as it would be pretty clearly a verifier bug that
would be silently missed since the return type is void.

  reply	other threads:[~2022-11-15 16:58 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-14 19:15 [PATCH bpf-next v7 00/26] Allocated objects, BPF linked lists Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 01/26] bpf: Remove local kptr references in documentation Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 02/26] bpf: Remove BPF_MAP_OFF_ARR_MAX Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 03/26] bpf: Fix copy_map_value, zero_map_value Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 04/26] bpf: Support bpf_list_head in map values Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 05/26] bpf: Rename RET_PTR_TO_ALLOC_MEM Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 06/26] bpf: Rename MEM_ALLOC to MEM_RINGBUF Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 07/26] bpf: Refactor btf_struct_access Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 08/26] bpf: Introduce allocated objects support Kumar Kartikeya Dwivedi
2022-11-15  5:48   ` Alexei Starovoitov
2022-11-15 16:47     ` Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 09/26] bpf: Recognize lock and list fields in allocated objects Kumar Kartikeya Dwivedi
2022-11-15  5:50   ` Alexei Starovoitov
2022-11-15 16:48     ` Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 10/26] bpf: Verify ownership relationships for user BTF types Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 11/26] bpf: Allow locking bpf_spin_lock in allocated objects Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 12/26] bpf: Allow locking bpf_spin_lock global variables Kumar Kartikeya Dwivedi
2022-11-15 17:33   ` Dave Marchevsky
2022-11-15 19:37     ` Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 13/26] bpf: Allow locking bpf_spin_lock in inner map values Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 14/26] bpf: Rewrite kfunc argument handling Kumar Kartikeya Dwivedi
2022-11-15  6:10   ` Alexei Starovoitov
2022-11-15 16:51     ` Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 15/26] bpf: Drop kfunc bits from btf_check_func_arg_match Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 16/26] bpf: Support constant scalar arguments for kfuncs Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 17/26] bpf: Introduce bpf_obj_new Kumar Kartikeya Dwivedi
2022-11-15  6:19   ` Alexei Starovoitov
2022-11-15 16:53     ` Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 18/26] bpf: Introduce bpf_obj_drop Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 19/26] bpf: Permit NULL checking pointer with non-zero fixed offset Kumar Kartikeya Dwivedi
2022-11-15  6:23   ` Alexei Starovoitov
2022-11-15 16:57     ` Kumar Kartikeya Dwivedi [this message]
2022-11-14 19:15 ` [PATCH bpf-next v7 20/26] bpf: Introduce single ownership BPF linked list API Kumar Kartikeya Dwivedi
2022-11-15  6:26   ` Alexei Starovoitov
2022-11-15 16:59     ` Kumar Kartikeya Dwivedi
2022-11-15 18:26       ` Alexei Starovoitov
2022-11-15 19:36         ` Kumar Kartikeya Dwivedi
2022-11-15 19:45           ` Alexei Starovoitov
2022-11-14 19:15 ` [PATCH bpf-next v7 21/26] bpf: Add 'release on unlock' logic for bpf_list_push_{front,back} Kumar Kartikeya Dwivedi
2022-11-15 16:52   ` Dave Marchevsky
2022-11-15 17:01     ` Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 22/26] selftests/bpf: Add __contains macro to bpf_experimental.h Kumar Kartikeya Dwivedi
2022-11-15 16:40   ` Dave Marchevsky
2022-11-14 19:15 ` [PATCH bpf-next v7 23/26] selftests/bpf: Update spinlock selftest Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 24/26] selftests/bpf: Add failure test cases for spin lock pairing Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 25/26] selftests/bpf: Add BPF linked list API tests Kumar Kartikeya Dwivedi
2022-11-14 19:15 ` [PATCH bpf-next v7 26/26] selftests/bpf: Add BTF sanity tests Kumar Kartikeya Dwivedi
2022-11-15  6:00 ` [PATCH bpf-next v7 00/26] Allocated objects, BPF linked lists patchwork-bot+netdevbpf

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