From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 631491CC159; Thu, 3 Oct 2024 22:37:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727995059; cv=none; b=VbQn68kSL6aOBgvwjwICrytl5jzs8z7S+9novm0rWPZVTdZcVgARVPb1r3ei2QX3d5p6u+j72hTctk5WXeKQLbfc5i+/mid4fyIlKf2tVcYL0/X4d1cJ/wp3Y/3tAnsK/N1zNHLW4pll2AdEuajBCmqasxVnpMmg8cTo3Rp+D0k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727995059; c=relaxed/simple; bh=aWOWsKOqJcRgMcWIVEktpgqJpsx0OOr0bf48J9P0VDU=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=r8YPQ33WhP0uH7XxkfkgEiWm6Yj9CfHQ3XMHHH/3zFCOsttZbyQe6Z6YCDCUG/3vcdzdVm5blwHnls/fLE8FgoeVf/zV+k+n0s4AFnnLZ0NGE50V8GZ8Nx7X4rbCtdz1G4IHRvHTppST4ZMmdaKBl+qZymgwWeur18qtyZu+eno= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2C2EC4CEC5; Thu, 3 Oct 2024 22:37:36 +0000 (UTC) Date: Thu, 3 Oct 2024 18:38:30 -0400 From: Steven Rostedt To: Mathieu Desnoyers Cc: Masami Hiramatsu , linux-kernel@vger.kernel.org, Peter Zijlstra , Alexei Starovoitov , Yonghong Song , "Paul E . McKenney" , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Namhyung Kim , Andrii Nakryiko , bpf@vger.kernel.org, Joel Fernandes , linux-trace-kernel@vger.kernel.org, Andrii Nakryiko , Michael Jeanson Subject: Re: [PATCH v1 8/8] tracing/bpf: Add might_fault check to syscall probes Message-ID: <20241003183830.16155ec3@gandalf.local.home> In-Reply-To: <20241003151638.1608537-9-mathieu.desnoyers@efficios.com> References: <20241003151638.1608537-1-mathieu.desnoyers@efficios.com> <20241003151638.1608537-9-mathieu.desnoyers@efficios.com> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 3 Oct 2024 11:16:38 -0400 Mathieu Desnoyers wrote: > Add a might_fault() check to validate that the bpf sys_enter/sys_exit > probe callbacks are indeed called from a context where page faults can > be handled. > > Signed-off-by: Mathieu Desnoyers > Acked-by: Andrii Nakryiko > Tested-by: Andrii Nakryiko # BPF parts > Cc: Michael Jeanson > Cc: Steven Rostedt > Cc: Masami Hiramatsu > Cc: Peter Zijlstra > Cc: Alexei Starovoitov > Cc: Yonghong Song > Cc: Paul E. McKenney > Cc: Ingo Molnar > Cc: Arnaldo Carvalho de Melo > Cc: Mark Rutland > Cc: Alexander Shishkin > Cc: Namhyung Kim > Cc: Andrii Nakryiko > Cc: bpf@vger.kernel.org > Cc: Joel Fernandes > --- > include/trace/bpf_probe.h | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h > index 211b98d45fc6..099df5c3e38a 100644 > --- a/include/trace/bpf_probe.h > +++ b/include/trace/bpf_probe.h > @@ -57,6 +57,7 @@ __bpf_trace_##call(void *__data, proto) \ > static notrace void \ > __bpf_trace_##call(void *__data, proto) \ > { \ > + might_fault(); \ And I think this gets called at places that do not allow faults. -- Steve > guard(preempt_notrace)(); \ > CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(__data, CAST_TO_U64(args)); \ > }