From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 B4BF045629C for ; Wed, 12 Aug 2026 14:28:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786544916; cv=none; b=UCq5H8hNBG/D8mGYIn4APVdLnal+6TM5HSQk2MGho2sXDgEr7sdpR9y42Lqm4S65WKW6BzVxhygKUizQUW4iPoVfpEcz+R2o/spYMBjpbuAX0vm7mLHZufHncWl0giI0CmFFVLsG7sAQMmxmxQQ2vF831FCEeCgmL1/e/QMvwto= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786544916; c=relaxed/simple; bh=xbLLdFkxwAnttK5vCKBF5AEV8qrKwRwOvtVYDl2CNoc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Oq+W4n9cv9rZYIj+HlBZeX8i3WPLbc5Ao/uljEOtAv/FebVH4zGthZm9GstUqMNYNNQ1tyMh39A8U965MSFLkeA6TNWwfgpaFWokPasMvysNaHOo8tG/FpoBtldw4Jjq7czIzB++BUhQX2A4EMWqqtml35sSAIH25mtWitBSvJo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=d+boFNcX; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="d+boFNcX" Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 67CE1cSf3717222 for ; Wed, 12 Aug 2026 14:28:31 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=pp1; bh=Ofy99CYOa09yHyOGErwiy8ZAwTvjX1 eSTaNFG6qLE8Q=; b=d+boFNcX6QGS8yD+dr09I4TLSn+rVoRi25X+Pa5nv1AS2A iV7KXbaxtsV68Jaa5cav6VnWT7tm8m06hkiBhzi8im9xPnGilET/nnKca9uHNe5e j7C47E2PQ6qdoS6Fl9S1bemGWceU2HQNefYwYBb3Lx9sFCr5OuFlt0RfRf6k9cp1 82e2ffVk1WZ45jYb4Hwx//oUzbPu2g8DxUmYMr7Au31a5tMleayi9xCKhUQS9y8c HGyslSXB3rAThF5JlmOLjZb2fY374Hvlx0nFS1R5DvYkaXTkVnbYHiD//ug+1Ybv +VOD+rcQfJRzOLrOt4Kg4b2n7eNzmFTqbJq7pU7g== Received: from ppma11.dal12v.mail.ibm.com (db.9e.1632.ip4.static.sl-reverse.com [50.22.158.219]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4fwvnwa35h-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 12 Aug 2026 14:28:31 +0000 (GMT) Received: from pps.filterd (ppma11.dal12v.mail.ibm.com [127.0.0.1]) by ppma11.dal12v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 67CEQY0o011534 for ; Wed, 12 Aug 2026 14:28:30 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma11.dal12v.mail.ibm.com (PPS) with ESMTPS id 4fxhfy66v7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 12 Aug 2026 14:28:30 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (smtpav03.fra02v.mail.ibm.com [10.20.54.102]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 67CESQ6h49611124 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 12 Aug 2026 14:28:26 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 784B020043; Wed, 12 Aug 2026 14:28:26 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3DC8220040; Wed, 12 Aug 2026 14:28:26 +0000 (GMT) Received: from localhost (unknown [9.111.41.232]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 12 Aug 2026 14:28:26 +0000 (GMT) Date: Wed, 12 Aug 2026 16:28:24 +0200 From: Vasily Gorbik To: Peter Oberparleiter Cc: Heiko Carstens , Alexander Gordeev , linux-s390@vger.kernel.org, Ilya Leoshkevich Subject: Re: [PATCH] s390/debug: Fix deadlock during unregister Message-ID: References: <20260812075319.2007940-1-oberpar@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260812075319.2007940-1-oberpar@linux.ibm.com> X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=RsP16imK c=1 sm=1 tr=0 ts=6a7c830f cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=CNkE3Pl81vnWf-qNC4EA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: p7hp6DhDi8cAmYz-Pm0mqQwd9w_pH7WW X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODEyMDExNCBTYWx0ZWRfX/5mpO1hc36T2 UwRYtWNHlk/YP7I8gjWKj21CGoPzB9Sngc2n79DscHBKHWRLckyZpmbWubKx/5z1ZMhCIHTX1Lm sJQ2znVMnoKMcxHknhxiJV6WG+M1vgpEp8DBq3UjI8OkT9j9yifNCnYD/8XvpHV96BJDbYvEkG9 55kekIsX4yXHaI7gQrhtNwSw+J2y6XwWrXIxa8n9/Pq5MpsD4vD1Tf1ROmdmKQIJiqXj7MKSFie bP0K+MV/BHyrIULFAFjd7qrRBq+C374OC8n8hN+Xsr5cfn3IiKb9I2tEuchOn64pzG7QmvESbgu ITX5kg8gmHs2epXis86gYQxHXMK1BTOpBat/3iqKH10GJGdbipIqPp9lK3wAKWrupkWINT6V99f XXIhmkcRu+Xy9FScRZD6kdR95aiQqN4W/5t7k7vQ6skbFvF229tddQjJUnu4AWxv/Z4qYe4I8VY LcuCqdluLv2ClqcmXXw== X-Proofpoint-ORIG-GUID: p7hp6DhDi8cAmYz-Pm0mqQwd9w_pH7WW X-Proofpoint-Spam-Info: AW1haW4tMjYwODEyMDExNCBTYWx0ZWRfX5cavIZFgqg5l sBoO5n+WspDocJnCDHVLfTrxbL5SlwhfAHPP8wssrbD3GPBMcz4S2gRKZGElz99+i68b9Rg3aJF 0BDEIoavwr6KL21sTK/ppgFcDpohS38= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-12_04,2026-08-12_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 impostorscore=0 suspectscore=0 clxscore=1015 malwarescore=0 phishscore=0 adultscore=0 lowpriorityscore=0 priorityscore=1501 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608120114 On Wed, Aug 12, 2026 at 09:53:19AM +0200, Peter Oberparleiter wrote: > Unregistering an s390dbf debug area while one of the associated debugfs > files is being written to can cause a deadlock: > > $ echo >.../vmur/level $ rmmod vmur > =================================================== > debugfs write > debugfs_file_get() > debug_unregister() > mutex_lock(debug_mutex) > debugfs_remove() > wait for debugfs_file_put() > debug_file_ops.write() > debug_input() > mutex_lock(debug_mutex) ==> DEADLOCK > > Fix this by splitting debug_unregister() into an s390dbf and debugfs > part, and running only the s390dbf part with debug_mutex locked. > > Signed-off-by: Peter Oberparleiter > --- > arch/s390/kernel/debug.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) Added Fixes: 9372a82892c2 ("s390/debug: fix debug area life cycle") and applied, thank you!