From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout.efficios.com (smtpout.efficios.com [167.114.26.122]) (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 285F81EE00C; Mon, 28 Oct 2024 20:27:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=167.114.26.122 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730147256; cv=none; b=p7ats6x+qoXJI61rUd0I/TwZ7g1U/sUwkgDtvrO2BJ4D/GuAdXuaB8E9+Sa6TBsXwPv/UMnme79bQb6pI397uMG6Ln9KgeEM9cthXmoBm/YCcsYnET+XLivKmEkQy8c36wovdXJlxjBA1eAbUBpo8Y9XRf9b9qOlilsrP05dLfo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730147256; c=relaxed/simple; bh=XDAZhSYAaVkmM4dFq8nal7tVXdbanH7syiZOM+auQxs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=dPpsXwDT7BFF3Lq9g+VFeM2UahhxR6VODvdMCHfmc95iJkihuCLjwNxnplG/dWHo87em5LwqGjOjygTtTG2IwgOwcHkHK9OHG8CIfynUhLFqUcKR5+NWIa1yd+qvsUxh0dHv/6faSOzo+DU4T7RPDE2HapMgez1VMBZRX2gkb2w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b=gCA0o8iF; arc=none smtp.client-ip=167.114.26.122 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="gCA0o8iF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=efficios.com; s=smtpout1; t=1730147253; bh=XDAZhSYAaVkmM4dFq8nal7tVXdbanH7syiZOM+auQxs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=gCA0o8iFNotPHu8YJdQ0zgNyNddjKrHOyPHkS6d9zzTRQz5Q1SCYa0bMXEkcKbeIi OZhocwgEgC0ajHj8oGg7IUU3x97Std4QUSTxP0zzqIIcGwrKoVZBpt5Tiqzapxxwud mH7eD2HAtr+VeC/6U2fNQbyeUnoR2MEqcIiY1O1O2baVSHUmA//dQMwNBAE3gz37Wj PQfzXlfdLD5BgMNs11HMkz3NUVd1bc9/zJPgHXpjq/Fog6NUidwJahkD87XPcm+p2W Lerc1xiM2ekLyfsQ/8G0zvIxL7YzysPx5eCujNwA7qlnJQ4nfpL2tybvvmuI9wGBAo e/jd3fgcxHT5g== Received: from [172.16.0.134] (96-127-217-162.qc.cable.ebox.net [96.127.217.162]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4XclLX62mRzsb2; Mon, 28 Oct 2024 16:27:32 -0400 (EDT) Message-ID: <588eb8e1-5035-499f-b19b-8b40a9877433@efficios.com> Date: Mon, 28 Oct 2024 16:25:53 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v4 4/4] tracing: Add might_fault() check in __DO_TRACE() for syscall To: Andrii Nakryiko , Jordan Rife Cc: Steven Rostedt , linux-kernel@vger.kernel.org, Thomas Gleixner , Michael Jeanson , Masami Hiramatsu , Peter Zijlstra , Alexei Starovoitov , Yonghong Song , "Paul E . McKenney" , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Namhyung Kim , bpf@vger.kernel.org, Joel Fernandes References: <20241028190927.648953-1-mathieu.desnoyers@efficios.com> <20241028190927.648953-5-mathieu.desnoyers@efficios.com> From: Mathieu Desnoyers Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2024-10-28 16:20, Andrii Nakryiko wrote: > On Mon, Oct 28, 2024 at 12:59 PM Mathieu Desnoyers > wrote: >> >> On 2024-10-28 15:09, Mathieu Desnoyers wrote: >>> Catch incorrect use of syscall tracepoints even if no probes are >>> registered by adding a might_fault() check in __DO_TRACE() when >>> syscall=1. >>> >>> Suggested-by: Thomas Gleixner >>> Signed-off-by: Mathieu Desnoyers >>> Cc: Thomas Gleixner >>> 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 >>> Cc: Jordan Rife >>> --- >>> include/linux/tracepoint.h | 6 ++++-- >>> 1 file changed, 4 insertions(+), 2 deletions(-) >>> >>> diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h >>> index 259f0ab4ece6..7bed499b7055 100644 >>> --- a/include/linux/tracepoint.h >>> +++ b/include/linux/tracepoint.h >>> @@ -226,10 +226,12 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) >>> if (!(cond)) \ >>> return; \ >>> \ >>> - if (syscall) \ >>> + if (syscall) { \ >>> rcu_read_lock_trace(); \ >>> - else \ >>> + might_fault(); \ >> >> Actually, __DO_TRACE() is not the best place to put this, because it's >> only executed when the tracepoint is enabled. >> >> I'll move this to __DECLARE_TRACE_SYSCALL() >> >> #define __DECLARE_TRACE_SYSCALL(name, proto, args, cond, data_proto) \ >> __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), cond, PARAMS(data_proto)) \ >> static inline void trace_##name(proto) \ >> { \ >> might_fault(); \ >> if (static_branch_unlikely(&__tracepoint_##name.key)) \ >> __DO_TRACE(name, \ >> TP_ARGS(args), \ >> TP_CONDITION(cond), 1); \ >> [...] >> >> instead in v5. > > please drop the RFC tag while at it I'm still awaiting for Jordan (or someone else) to come back with testing results before I feel confident dropping the RFC tag. Thanks, Mathieu > >> >> Thanks, >> >> Mathieu >> >>> + } else { \ >>> preempt_disable_notrace(); \ >>> + } \ >>> \ >>> __DO_TRACE_CALL(name, TP_ARGS(args)); \ >>> \ >> >> -- >> Mathieu Desnoyers >> EfficiOS Inc. >> https://www.efficios.com >> -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com