From: Tejun Heo <tj@kernel.org>
To: Yonghong Song <yonghong.song@linux.dev>
Cc: bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
kernel-team@fb.com, Martin KaFai Lau <martin.lau@kernel.org>
Subject: Re: [PATCH bpf-next v7 8/9] bpf: Support private stack for struct_ops progs
Date: Wed, 30 Oct 2024 13:14:52 -1000 [thread overview]
Message-ID: <ZyK97MokcVLgoFrQ@slm.duckdns.org> (raw)
In-Reply-To: <20241029221718.268017-1-yonghong.song@linux.dev>
Hello,
On Tue, Oct 29, 2024 at 03:17:18PM -0700, Yonghong Song wrote:
> For struct_ops progs, whether a particular prog will use private stack
> or not (prog->aux->use_priv_stack) will be set before actual insn-level
> verification for that prog. One particular implementation is to
> piggyback on struct_ops->check_member(). The next patch will have an
> example for this. The struct_ops->check_member() will set
> prog->aux->use_priv_stack to be true which enables private stack
> usage with ignoring BPF_PRIV_STACK_MIN_SIZE limit.
>
> If use_priv_stack is true for a particular struct_ops prog, bpf
> trampoline will need to do recursion checks (one level at this point)
> to avoid stack overwrite.
>
> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
From sched_ext usage POV:
Acked-by: Tejun Heo <tj@kernel.org>
Thanks.
--
tejun
next prev parent reply other threads:[~2024-10-30 23:14 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-29 22:16 [PATCH bpf-next v7 0/9] bpf: Support private stack for bpf progs Yonghong Song
2024-10-29 22:16 ` [PATCH bpf-next v7 1/9] bpf: Check stack depth limit after visiting all subprogs Yonghong Song
2024-10-29 22:16 ` [PATCH bpf-next v7 2/9] bpf: Allow private stack to have each subprog having stack size of 512 bytes Yonghong Song
2024-10-29 22:16 ` [PATCH bpf-next v7 3/9] bpf: Check potential private stack recursion for progs with async callback Yonghong Song
2024-10-29 22:16 ` [PATCH bpf-next v7 4/9] bpf: Allocate private stack for eligible main prog or subprogs Yonghong Song
2024-10-29 22:17 ` [PATCH bpf-next v7 5/9] bpf, x86: Avoid repeated usage of bpf_prog->aux->stack_depth Yonghong Song
2024-10-29 22:17 ` [PATCH bpf-next v7 6/9] bpf, x86: Support private stack in jit Yonghong Song
2024-10-29 22:17 ` [PATCH bpf-next v7 7/9] selftests/bpf: Add tracing prog private stack tests Yonghong Song
2024-10-29 22:17 ` [PATCH bpf-next v7 8/9] bpf: Support private stack for struct_ops progs Yonghong Song
2024-10-30 23:14 ` Tejun Heo [this message]
2024-10-29 22:17 ` [PATCH bpf-next v7 9/9] selftests/bpf: Add struct_ops prog private stack tests Yonghong Song
2024-10-30 23:29 ` Tejun Heo
2024-10-31 19:37 ` Yonghong Song
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