Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 1 Feb 2021 10:22:27 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Dmitry Vyukov <dvyukov@google.com>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>, andrii@kernel.org,
        Martin KaFai Lau <kafai@fb.com>,
        David Miller <davem@davemloft.net>, kpsingh@kernel.org,
        John Fastabend <john.fastabend@gmail.com>,
        netdev <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: extended bpf_send_signal_thread with argument
Message-ID: <YBfIUwtK+QqVlfRt@hirez.programming.kicks-ass.net>
References: <CACT4Y+a7UBQpAY4vwT8Od0JhwbwcDrbJXZ_ULpPfJZ42Ew-yCQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CACT4Y+a7UBQpAY4vwT8Od0JhwbwcDrbJXZ_ULpPfJZ42Ew-yCQ@mail.gmail.com>
Precedence: bulk

On Sun, Jan 31, 2021 at 12:14:02PM +0100, Dmitry Vyukov wrote:
> Hi,
> 
> I would like to send a signal from a bpf program invoked from a
> perf_event. There is:

You can't. Sending signals requires sighand lock, and you're not allowed
to take locks from perf_event context.