From: Greg KH <gregkh@linuxfoundation.org>
To: Edward Liaw <edliaw@google.com>
Cc: stable@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"David S. Miller" <davem@davemloft.net>,
bpf@vger.kernel.org, kernel-team@android.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
John Fastabend <john.fastabend@gmail.com>,
Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Subject: Re: [PATCH 4.14 v2 1/4] bpf: Do not use ax register in interpreter on div/mod
Date: Thu, 23 Feb 2023 10:01:40 +0100 [thread overview]
Message-ID: <Y/crdG+quVvKMF0m@kroah.com> (raw)
In-Reply-To: <20230222192925.1778183-2-edliaw@google.com>
On Wed, Feb 22, 2023 at 07:29:21PM +0000, Edward Liaw wrote:
> From: Daniel Borkmann <daniel@iogearbox.net>
>
> Partially undo old commit 144cd91c4c2b ("bpf: move tmp variable into ax
> register in interpreter"). The reason we need this here is because ax
> register will be used for holding temporary state for div/mod instruction
> which otherwise interpreter would corrupt. This will cause a small +8 byte
> stack increase for interpreter, but with the gain that we can use it from
> verifier rewrites as scratch register.
>
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Reviewed-by: John Fastabend <john.fastabend@gmail.com>
> [cascardo: This partial revert is needed in order to support using AX for
> the following two commits, as there is no JMP32 on 4.19.y]
> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
> [edliaw: Removed redeclaration of tmp]
> Signed-off-by: Edward Liaw <edliaw@google.com>
> ---
> kernel/bpf/core.c | 31 ++++++++++++++-----------------
> 1 file changed, 14 insertions(+), 17 deletions(-)
What is the git commit id in Linus's tree of this commit?
thanks,
greg k-h
next prev parent reply other threads:[~2023-02-23 9:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-22 19:29 [PATCH 4.14 v2 0/4] BPF fixes for CVE-2021-3444 and CVE-2021-3600 Edward Liaw
2023-02-22 19:29 ` [PATCH 4.14 v2 1/4] bpf: Do not use ax register in interpreter on div/mod Edward Liaw
2023-02-22 19:30 ` kernel test robot
2023-02-23 9:01 ` Greg KH [this message]
2023-02-23 18:46 ` Edward Liaw
2023-02-23 20:09 ` Greg KH
2023-02-23 21:29 ` Edward Liaw
2023-02-22 19:29 ` [PATCH 4.14 v2 2/4] bpf: fix subprog verifier bypass by div/mod by 0 exception Edward Liaw
2023-02-22 19:29 ` [PATCH 4.14 v2 3/4] bpf: Fix 32 bit src register truncation on div/mod Edward Liaw
2023-02-22 19:29 ` [PATCH 4.14 v2 4/4] bpf: Fix truncation handling for mod32 dst reg wrt zero Edward Liaw
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