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 7379F824BD; Thu, 3 Oct 2024 22:36:46 +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=1727995006; cv=none; b=mZ52b1Z3xS/Ppsd9mIBIlyeKUBiGwQrkyJCDV0B9KP2mWBXr2CH+PFntljzpF3J60WpaSM/JXsz9a+ytsh6zBcCrP1F1IsB863/EHqzLnFBMa8gcCRrlRyccndyF8N9JgK/D7ciCZN6u2zirkSRm7c4c5n4NeoqUkwt3D4U8/ik= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727995006; c=relaxed/simple; bh=TVsn/95wWLL5iksakvNhZU0qqBQP0YTvnJq53+3O0Tg=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=fiwrCA1LX07Ik7slPUzaGNvHPObJXfZw7EJ922jjKF1VU/vbTBvr45UFJRom9nl6vKgxcqXyvYrj2DDc57m5+SEeP2XuzPg67HkZMM2xh8QCy8qaH4BLBzIfWWNGQTIi1oarEs8EUerJnWYM4zGrJm2/dZEn8lc9tnWm4onv4Ao= 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 1BC76C4CEC5; Thu, 3 Oct 2024 22:36:44 +0000 (UTC) Date: Thu, 3 Oct 2024 18:37:38 -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, Michael Jeanson Subject: Re: [PATCH v1 7/8] tracing/perf: Add might_fault check to syscall probes Message-ID: <20241003183738.4ebd97f9@gandalf.local.home> In-Reply-To: <20241003151638.1608537-8-mathieu.desnoyers@efficios.com> References: <20241003151638.1608537-1-mathieu.desnoyers@efficios.com> <20241003151638.1608537-8-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 11:16:37 -0400 Mathieu Desnoyers wrote: > Add a might_fault() check to validate that the perf sys_enter/sys_exit > probe callbacks are indeed called from a context where page faults can > be handled. > > Signed-off-by: Mathieu Desnoyers > 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/perf.h | 1 + > kernel/trace/trace_syscalls.c | 2 ++ > 2 files changed, 3 insertions(+) > > diff --git a/include/trace/perf.h b/include/trace/perf.h > index 5650c1bad088..321bfd7919f6 100644 > --- a/include/trace/perf.h > +++ b/include/trace/perf.h > @@ -84,6 +84,7 @@ perf_trace_##call(void *__data, proto) \ > u64 __count __attribute__((unused)); \ > struct task_struct *__task __attribute__((unused)); \ > \ > + might_fault(); \ > guard(preempt_notrace)(); \ > do_perf_trace_##call(__data, args); \ Same for this. This is used for all tracepoints that perf hooks to. -- Steve > } > diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c > index 89d7e4c57b5b..0d42d6f293d6 100644 > --- a/kernel/trace/trace_syscalls.c > +++ b/kernel/trace/trace_syscalls.c > @@ -602,6 +602,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) > * Syscall probe called with preemption enabled, but the ring > * buffer and per-cpu data require preemption to be disabled. > */ > + might_fault(); > guard(preempt_notrace)(); > > syscall_nr = trace_get_syscall_nr(current, regs); > @@ -710,6 +711,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) > * Syscall probe called with preemption enabled, but the ring > * buffer and per-cpu data require preemption to be disabled. > */ > + might_fault(); > guard(preempt_notrace)(); > > syscall_nr = trace_get_syscall_nr(current, regs);