From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "John Ogness" <john.ogness@linutronix.de>,
"Gabriele Monaco" <gmonaco@redhat.com>,
<linux-kernel@vger.kernel.org>,
<linux-trace-kernel@vger.kernel.org>, <bpf@vger.kernel.org>,
"Steven Rostedt" <rostedt@goodmis.org>
Cc: "Nam Cao" <namcao@linutronix.de>, "Wen Yang" <wen.yang@linux.dev>,
"Tobias Schaffner" <tobias.schaffner@siemens.com>,
"Viktor Malik" <vmalik@redhat.com>
Subject: Re: [PATCH v2 10/15] tools/rv: Add BPF monitors
Date: Sat, 17 Oct 2026 16:09:47 +0000 [thread overview]
Message-ID: <DM78SVMBI2XW.2XHVC67VON48A@gmail.com> (raw)
In-Reply-To: <87bj8s8ih9.fsf@jogness.linutronix.de>
On Sat, Oct 17, 2026 at 05:23 PM John Ogness <john.ogness@linutronix.de> wrote:
> That sounds like it could work. As long as there are kprobes in the call
> stack of violations, I am happy.
No need for a kfunc to get that.
bpf_printk() in the reactor is a regular bpf_trace:bpf_trace_printk
event, fired from the prog where the violation is detected.
ftrace triggers and perf can attach to it.
> A delayed kernel record is better than none. Although I really do not
> see why it cannot simply call printk_deferred() directly. It is safe and
> lockless. And it has the advantage of appropriate timestamping when
> compared to any other printk's that may be happening at that time.
>
> If we are already adding kfuncs for panics and violations, why the
> resistance to printks?
printk kfunc wouldn't be limited to rv. Any tracing prog would
be able to write to dmesg with no rate limit and then you, Petr
and others will start yelling that bpf is abusing printk
and dos-ing the rest of the kernel.
Hence let's avoid this can of worms.
next prev parent reply other threads:[~2026-10-17 16:09 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-01 15:20 [PATCH v2 00/15] rv: Add support for BPF monitors Gabriele Monaco
2026-10-01 15:20 ` [PATCH v2 01/15] sched: Add task enqueue/dequeue trace points Gabriele Monaco
2026-10-01 15:49 ` Peter Zijlstra
2026-10-02 7:09 ` Gabriele Monaco
2026-10-02 10:29 ` Peter Zijlstra
2026-10-02 11:55 ` Gabriele Monaco
2026-10-02 19:18 ` Peter Zijlstra
2026-10-02 19:40 ` Gabriele Monaco
2026-10-04 7:57 ` Steven Rostedt
2026-10-12 11:54 ` Peter Zijlstra
2026-10-04 7:45 ` Steven Rostedt
2026-10-12 11:49 ` Peter Zijlstra
2026-10-02 0:42 ` bot+bpf-ci
2026-10-01 15:20 ` [PATCH v2 02/15] tools/rv: Skip empty pid error in selftest if command failed Gabriele Monaco
2026-10-02 0:42 ` bot+bpf-ci
2026-10-01 15:20 ` [PATCH v2 03/15] rv: Refactor da_trace() functions to get strings internally Gabriele Monaco
2026-10-01 15:20 ` [PATCH v2 04/15] rv: Cast result of model_get_*_name() Gabriele Monaco
2026-10-13 6:14 ` Nam Cao
2026-10-13 8:15 ` Gabriele Monaco
2026-10-14 9:52 ` Gabriele Monaco
2026-10-14 10:02 ` Nam Cao
2026-10-01 15:20 ` [PATCH v2 05/15] tools/rv: Move argument parsing from in_kernel to utils Gabriele Monaco
2026-10-02 0:25 ` bot+bpf-ci
2026-10-01 15:20 ` [PATCH v2 06/15] tools/build: Add a feature test for bpftool-btf Gabriele Monaco
2026-10-01 15:20 ` [PATCH v2 07/15] tools/rv: Implement BPF monitor discovery and listing Gabriele Monaco
2026-10-01 15:40 ` sashiko-bot
2026-10-02 0:42 ` bot+bpf-ci
2026-10-01 15:20 ` [PATCH v2 08/15] tools/rv: Implement BPF monitor loading and tracing Gabriele Monaco
2026-10-01 15:41 ` sashiko-bot
2026-10-02 0:43 ` bot+bpf-ci
2026-10-01 15:20 ` [PATCH v2 09/15] tools/rv: Copy stripped bpf_atomic.h from libarena Gabriele Monaco
2026-10-02 0:42 ` bot+bpf-ci
2026-10-07 12:59 ` Nam Cao
2026-10-08 9:00 ` Gabriele Monaco
2026-10-08 11:16 ` Nam Cao
2026-10-09 10:09 ` Gabriele Monaco
2026-10-11 0:43 ` Steven Rostedt
2026-10-12 7:43 ` Gabriele Monaco
2026-10-01 15:20 ` [PATCH v2 10/15] tools/rv: Add BPF monitors Gabriele Monaco
2026-10-01 15:55 ` sashiko-bot
2026-10-02 0:43 ` bot+bpf-ci
2026-10-06 13:29 ` Alexei Starovoitov
2026-10-08 9:54 ` Gabriele Monaco
2026-10-16 18:32 ` Alexei Starovoitov
2026-10-16 19:20 ` John Ogness
2026-10-17 10:42 ` Gabriele Monaco
2026-10-17 15:17 ` John Ogness
2026-10-17 16:09 ` Alexei Starovoitov [this message]
2026-10-17 16:56 ` John Ogness
2026-10-17 10:48 ` Gabriele Monaco
2026-10-01 15:20 ` [PATCH v2 11/15] tools/rv: Define CONFIG_X86_64 statically for " Gabriele Monaco
2026-10-01 15:49 ` sashiko-bot
2026-10-01 15:20 ` [PATCH v2 12/15] tools/rv: Add reactors support to " Gabriele Monaco
2026-10-01 15:57 ` sashiko-bot
2026-10-02 0:43 ` bot+bpf-ci
2026-10-01 15:20 ` [PATCH v2 13/15] verification/rvgen: Add support for " Gabriele Monaco
2026-10-02 0:25 ` bot+bpf-ci
2026-10-01 15:20 ` [PATCH v2 14/15] tools/rv: Add selftest for rv bpf monitors Gabriele Monaco
2026-10-01 16:03 ` sashiko-bot
2026-10-02 0:43 ` bot+bpf-ci
2026-10-01 15:20 ` [PATCH v2 15/15] verification/rvgen: Add selftest for rvgen -b Gabriele Monaco
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