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Wed, 20 Jan 2021 13:42:10 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AFEBEA4053; Wed, 20 Jan 2021 13:42:09 +0000 (GMT) Received: from osiris (unknown [9.171.38.241]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Wed, 20 Jan 2021 13:42:09 +0000 (GMT) Date: Wed, 20 Jan 2021 14:42:08 +0100 From: Heiko Carstens To: Christian Borntraeger Cc: Janosch Frank , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, thuth@redhat.com, david@redhat.com, imbrenda@linux.ibm.com, cohuck@redhat.com, linux-s390@vger.kernel.org, gor@linux.ibm.com, mihajlov@linux.ibm.com Subject: Re: [PATCH 2/2] s390: mm: Fix secure storage access exception handling Message-ID: <20210120134208.GC8202@osiris> References: <20210119100402.84734-1-frankja@linux.ibm.com> <20210119100402.84734-3-frankja@linux.ibm.com> <3e1978c6-4462-1de6-e1aa-e664ffa633c1@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3e1978c6-4462-1de6-e1aa-e664ffa633c1@de.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.343,18.0.737 definitions=2021-01-20_05:2021-01-20,2021-01-20 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 adultscore=0 mlxscore=0 mlxlogscore=798 impostorscore=0 lowpriorityscore=0 clxscore=1011 malwarescore=0 phishscore=0 spamscore=0 priorityscore=1501 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101200079 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Jan 19, 2021 at 11:25:01AM +0100, Christian Borntraeger wrote: > > + if (user_mode(regs)) { > > + send_sig(SIGSEGV, current, 0); > > + return; > > + } else > > + panic("Unexpected PGM 0x3d with TEID bit 61=0"); > > use BUG instead of panic? That would kill this process, but it allows > people to maybe save unaffected data. It would kill the process, and most likely lead to deadlock'ed system. But with all the "good" debug information being lost, which wouldn't be the case with panic(). I really don't think this is a good idea.