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Fri, 24 Jan 2025 16:41:35 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 334712004E; Fri, 24 Jan 2025 16:41:35 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 74ED920063; Fri, 24 Jan 2025 16:41:30 +0000 (GMT) Received: from [9.171.221.90] (unknown [9.171.221.90]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 24 Jan 2025 16:41:30 +0000 (GMT) Message-ID: Date: Fri, 24 Jan 2025 17:41:29 +0100 Precedence: bulk X-Mailing-List: linux-toolchains@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Jens Remus Subject: Re: [PATCH v4 11/39] unwind_user: Add user space unwinding API To: Josh Poimboeuf , x86@kernel.org Cc: Peter Zijlstra , Steven Rostedt , Ingo Molnar , Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, Indu Bhagat , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , linux-perf-users@vger.kernel.org, Mark Brown , linux-toolchains@vger.kernel.org, Jordan Rome , Sam James , linux-trace-kernel@vger.kernel.org, Andrii Nakryiko , Mathieu Desnoyers , Florian Weimer , Andy Lutomirski , Masami Hiramatsu , Weinan Liu , Heiko Carstens , Vasily Gorbik References: Content-Language: en-US Organization: IBM Deutschland Research & Development GmbH In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: wbSlex12wuwgX1COk8JMgE6oZ_9p0UQ3 X-Proofpoint-GUID: mhh1lIdnBO30qN-S9J-fB9OrNsalXKP5 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-01-24_07,2025-01-23_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 priorityscore=1501 impostorscore=0 clxscore=1015 lowpriorityscore=0 bulkscore=0 mlxlogscore=999 mlxscore=0 malwarescore=0 spamscore=0 suspectscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2501240116 On 22.01.2025 03:31, Josh Poimboeuf wrote: > diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c > @@ -0,0 +1,59 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > +* Generic interfaces for unwinding user space > +*/ > +#include > +#include > +#include > +#include > + > +int unwind_user_next(struct unwind_user_state *state) > +{ > + struct unwind_user_frame _frame; > + struct unwind_user_frame *frame = &_frame; > + unsigned long cfa = 0, fp, ra = 0; Why are cfa and ra initialized to zero? Where is that important in subsequent patches? "[PATCH v4 12/39] unwind_user: Add frame pointer support" does either unconditionally set both cfa and ra or bail out. > + > + /* no implementation yet */ > + -EINVAL; > +} Thanks and regards, Jens -- Jens Remus Linux on Z Development (D3303) +49-7031-16-1128 Office jremus@de.ibm.com IBM IBM Deutschland Research & Development GmbH; Vorsitzender des Aufsichtsrats: Wolfgang Wendt; Geschäftsführung: David Faller; Sitz der Gesellschaft: Böblingen; Registergericht: Amtsgericht Stuttgart, HRB 243294 IBM Data Privacy Statement: https://www.ibm.com/privacy/