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From: Martin Lau <kafai@fb.com>
To: Paul Chaignon <paul.chaignon@orange.com>
Cc: "Paul Burton" <paulburton@kernel.org>,
	"Björn Töpel" <bjorn.topel@gmail.com>,
	"Mahshid Khezri" <khezri.mahshid@gmail.com>,
	"paul.chaignon@gmail.com" <paul.chaignon@gmail.com>,
	"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
	"Andrii Nakryiko" <andriin@fb.com>
Subject: Re: [PATCH bpf 0/2] Limit tail calls to 33 in all JIT compilers
Date: Tue, 10 Dec 2019 18:19:32 +0000	[thread overview]
Message-ID: <20191210181929.477nstc4vcccecyc@kafai-mbp> (raw)
In-Reply-To: <cover.1575916815.git.paul.chaignon@gmail.com>

On Mon, Dec 09, 2019 at 07:51:52PM +0100, Paul Chaignon wrote:
> The BPF interpreter and all JIT compilers, except RISC-V's and MIPS',
> enforce a 33-tail calls limit at runtime.  Because of this discrepancy, a
> BPF program can have a different behavior and output depending on whether
> it is interpreted or JIT compiled, or depending on the underlying
> architecture.
> 
> This patchset changes the RISC-V and MIPS JIT compilers to limit tail
> calls to 33 instead of 32.  I have checked other BPF JIT compilers for the
> same discrepancy.
Acked-by: Martin KaFai Lau <kafai@fb.com>

  parent reply	other threads:[~2019-12-10 18:20 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-09 18:51 [PATCH bpf 0/2] Limit tail calls to 33 in all JIT compilers Paul Chaignon
2019-12-09 18:52 ` [PATCH bpf 1/2] bpf, riscv: limit to 33 tail calls Paul Chaignon
2019-12-09 19:57   ` Björn Töpel
2019-12-10  6:31     ` Björn Töpel
2019-12-10  9:36     ` Paul Chaignon
2019-12-09 18:52 ` [PATCH bpf 2/2] bpf, mips: " Paul Chaignon
2019-12-10 23:23   ` Paul Burton
2019-12-12 16:19     ` Daniel Borkmann
2019-12-18  9:32     ` Alexander Lobakin
2019-12-18  9:58       ` Paul Chaignon
2019-12-18 10:02         ` Alexander Lobakin
2019-12-10 18:19 ` Martin Lau [this message]
2019-12-11 13:00 ` [PATCH bpf 0/2] Limit tail calls to 33 in all JIT compilers Daniel Borkmann

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