From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Alan Maguire <alan.maguire@oracle.com>
Cc: ardb@kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Alexei Starovoitov <ast@kernel.org>,
Zi Shen Lim <zlim.lnx@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>, Martin Lau <kafai@fb.com>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
john fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
andreyknvl@gmail.com, vincenzo.frascino@arm.com,
Mark Rutland <mark.rutland@arm.com>,
Sami Tolvanen <samitolvanen@google.com>,
joey.gouly@arm.com, maz@kernel.org, daizhiyuan@phytium.com.cn,
jthierry@redhat.com, Tian Tao <tiantao6@hisilicon.com>,
Peter Collingbourne <pcc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
rppt@kernel.org, Jisheng.Zhang@synaptics.com,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
open list <linux-kernel@vger.kernel.org>,
Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH v2 bpf-next 2/2] selftests/bpf: add exception handling selftests for tp_bpf program
Date: Fri, 5 Nov 2021 11:54:27 -0700 [thread overview]
Message-ID: <CAEf4BzaCmCM5zuSrtUDvR8Y+nf=3FF8+mSjQHytn=N5fBZV40w@mail.gmail.com> (raw)
In-Reply-To: <1636131046-5982-3-git-send-email-alan.maguire@oracle.com>
On Fri, Nov 5, 2021 at 10:11 AM Alan Maguire <alan.maguire@oracle.com> wrote:
>
> Exception handling is triggered in BPF tracing programs when
> a NULL pointer is dereferenced; the exception handler zeroes the
> target register and execution of the BPF program progresses.
>
> To test exception handling then, we need to trigger a NULL pointer
> dereference for a field which should never be zero; if it is, the
> only explanation is the exception handler ran. task->task_works
> is the NULL pointer chosen (for a new task from fork() no work
> is associated), and the task_works->func field should not be zero
> if task_works is non-NULL. Test verifies task_works and
> task_works->func are 0.
>
> Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
> ---
> tools/testing/selftests/bpf/prog_tests/exhandler.c | 43 ++++++++++++++++++++++
> tools/testing/selftests/bpf/progs/exhandler_kern.c | 43 ++++++++++++++++++++++
> 2 files changed, 86 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/exhandler.c
> create mode 100644 tools/testing/selftests/bpf/progs/exhandler_kern.c
>
The test looks good, thank you!
Acked-by: Andrii Nakryiko <andrii@kernel.org>
[...]
next prev parent reply other threads:[~2021-11-05 18:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-05 16:50 [PATCH v2 bpf-next 0/2] arm64/bpf: remove 128MB limit for BPF JIT programs Alan Maguire
2021-11-05 16:50 ` [PATCH v2 bpf-next 1/2] " Alan Maguire
2021-11-05 16:50 ` [PATCH v2 bpf-next 2/2] selftests/bpf: add exception handling selftests for tp_bpf program Alan Maguire
2021-11-05 18:54 ` Andrii Nakryiko [this message]
2021-11-08 21:30 ` [PATCH v2 bpf-next 0/2] arm64/bpf: remove 128MB limit for BPF JIT programs patchwork-bot+netdevbpf
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