From: Brendan Jackman <jackmanb@google.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Yonghong Song <yhs@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
KP Singh <kpsingh@chromium.org>,
Florent Revest <revest@chromium.org>
Subject: Re: [PATCH 5/7] bpf: Add BPF_FETCH field / create atomic_fetch_add instruction
Date: Tue, 24 Nov 2020 10:48:17 +0000 [thread overview]
Message-ID: <20201124104817.GA1883487@google.com> (raw)
In-Reply-To: <20201124065257.456bpoy4r5pf67xz@ast-mbp>
On Mon, Nov 23, 2020 at 10:52:57PM -0800, Alexei Starovoitov wrote:
> On Mon, Nov 23, 2020 at 05:32:00PM +0000, Brendan Jackman wrote:
> > @@ -3644,8 +3649,21 @@ static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_i
> > return err;
> >
> > /* check whether we can write into the same memory */
> > - return check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
> > - BPF_SIZE(insn->code), BPF_WRITE, -1, true);
> > + err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
> > + BPF_SIZE(insn->code), BPF_WRITE, -1, true);
> > + if (err)
> > + return err;
> > +
> > + if (!(insn->imm & BPF_FETCH))
> > + return 0;
> > +
> > + /* check and record load of old value into src reg */
> > + err = check_reg_arg(env, insn->src_reg, DST_OP);
> > + if (err)
> > + return err;
> > + regs[insn->src_reg].type = SCALAR_VALUE;
>
> check_reg_arg() will call mark_reg_unknown() which will set type to SCALAR_VALUE.
> What is the point of another assignment?
Yep, this is just an oversight - thanks, will remove.
next prev parent reply other threads:[~2020-11-24 10:48 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-23 17:31 [PATCH 0/7] Atomics for eBPF Brendan Jackman
2020-11-23 17:31 ` [PATCH 1/7] bpf: Factor out emission of ModR/M for *(reg + off) Brendan Jackman
2020-11-23 17:31 ` [PATCH 2/7] bpf: x86: Factor out emission of REX byte Brendan Jackman
2020-11-23 17:31 ` [PATCH 3/7] bpf: Rename BPF_XADD and prepare to encode other atomics in .imm Brendan Jackman
2020-11-23 23:54 ` Yonghong Song
2020-11-24 11:02 ` Brendan Jackman
2020-11-24 16:04 ` Yonghong Song
2020-11-24 3:28 ` kernel test robot
2020-11-24 6:50 ` Alexei Starovoitov
2020-11-24 11:21 ` Brendan Jackman
2020-11-24 22:43 ` Alexei Starovoitov
2020-11-23 17:31 ` [PATCH 4/7] bpf: Move BPF_STX reserved field check into BPF_STX verifier code Brendan Jackman
2020-11-23 17:32 ` [PATCH 5/7] bpf: Add BPF_FETCH field / create atomic_fetch_add instruction Brendan Jackman
2020-11-23 21:12 ` kernel test robot
2020-11-23 21:51 ` kernel test robot
2020-11-24 6:52 ` Alexei Starovoitov
2020-11-24 10:48 ` Brendan Jackman [this message]
2020-11-23 17:32 ` [PATCH 6/7] bpf: Add instructions for atomic_cmpxchg and friends Brendan Jackman
2020-11-23 19:29 ` Brendan Jackman
2020-11-24 6:40 ` Alexei Starovoitov
2020-11-24 10:55 ` Brendan Jackman
2020-11-24 22:51 ` Alexei Starovoitov
2020-11-23 17:32 ` [PATCH 7/7] bpf: Add tests for new BPF atomic operations Brendan Jackman
2020-11-24 0:26 ` Yonghong Song
2020-11-24 13:10 ` Brendan Jackman
2020-11-23 17:36 ` [PATCH 0/7] Atomics for eBPF Brendan Jackman
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