linux-kernel - Re: [PATCH] tracing/user_events: Run BPF program if attached

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Message-ID: <CAHk-=wjU0vq8aL_VmUDqwh9_fo8nXYt65PBjihNetTMq4s8OsA@mail.gmail.com>
Date:   Wed, 17 May 2023 17:23:17 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Beau Belgrave <beaub@...ux.microsoft.com>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        Alexei Starovoitov <alexei.starovoitov@...il.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-trace-kernel@...r.kernel.org,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>, bpf <bpf@...r.kernel.org>,
        David Vernet <void@...ifault.com>, dthaler@...rosoft.com,
        brauner@...nel.org, hch@...radead.org
Subject: Re: [PATCH] tracing/user_events: Run BPF program if attached

On Wed, May 17, 2023 at 5:14 PM Beau Belgrave <beaub@...ux.microsoft.com> wrote:
>
> Do you run with CONFIG_DEBUG_ATOMIC_SLEEP? It will not splat with just
> CONFIG_PROVE_LOCKING and CONFIG_PROVE_RCU, which bit me here. I'm now
> running all three now that I know better.

I wonder if we should just make PROVE_LOCKING select DEBUG_ATOMIC_SLEEP..

PROVE_LOCKING is the expensive and complicated one. In contrast,
DEBUG_ATOMIC_SLEEP is the "we've had this simplistic check for some
very basic requirements for a long time".

So DEBUG_ATOMIC_SLEEP is really just a minimal debugging thing, it
feels a bit silly to have all the expensive "prove locking with
lockdep and all our lock debugging", and then not test the trivial
basics.

           Linus