From: Eduard Zingerman <eddyz87@gmail.com>
To: Puranjay Mohan <puranjay@kernel.org>, bpf@vger.kernel.org
Cc: Puranjay Mohan <puranjay12@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@kernel.org>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>,
kernel-team@meta.com
Subject: Re: [PATCH bpf-next 2/2] selftests: bpf: Add test for multiple syncs from linked register
Date: Thu, 15 Jan 2026 10:46:05 -0800 [thread overview]
Message-ID: <b010e4c8352fffbbdec683cae4ad46b9bf5fa419.camel@gmail.com> (raw)
In-Reply-To: <20260115151143.1344724-3-puranjay@kernel.org>
On Thu, 2026-01-15 at 07:11 -0800, Puranjay Mohan wrote:
> Before the last commit, sync_linked_regs() corrupted the register whose
> bounds are being updated by copying known_reg's id to it. The ids are
> the same in value but known_reg has the BPF_ADD_CONST flag which is
> wrongly copied to reg.
>
> This later causes issues when creating new links to this reg.
> assign_scalar_id_before_mov() sees this BPF_ADD_CONST and gives a new id
> to this register and breaks the old links. This is exposed by the added
> selftest.
>
> Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
> ---
Confirm the test behavior on master vs master+patch #1.
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
[...]
next prev parent reply other threads:[~2026-01-15 18:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-15 15:11 [PATCH bpf-next 0/2] bpf: Fix linked register tracking Puranjay Mohan
2026-01-15 15:11 ` [PATCH bpf-next 1/2] bpf: Preserve id of register in sync_linked_regs() Puranjay Mohan
2026-01-15 18:39 ` Eduard Zingerman
2026-01-15 22:42 ` Andrii Nakryiko
2026-01-16 12:59 ` Puranjay Mohan
2026-01-16 3:08 ` Alexei Starovoitov
2026-01-16 13:01 ` Puranjay Mohan
2026-01-15 15:11 ` [PATCH bpf-next 2/2] selftests: bpf: Add test for multiple syncs from linked register Puranjay Mohan
2026-01-15 18:46 ` Eduard Zingerman [this message]
2026-01-16 18:30 ` [PATCH bpf-next 0/2] bpf: Fix linked register tracking patchwork-bot+netdevbpf
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