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Tue, 13 Oct 2026 11:55:29 +0000 (GMT) Received: from li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com (unknown [9.224.92.206]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTPS; Tue, 13 Oct 2026 11:55:29 +0000 (GMT) Date: Tue, 13 Oct 2026 13:55:28 +0200 From: Alexander Gordeev To: Heiko Carstens Cc: Sven Schnelle , Vasily Gorbik , Christian Borntraeger , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: Re: [PATCH 2/2] s390/entry: Save lowcore on invalid kernel stack Message-ID: <0032a4a4-1a4f-4665-a3dd-5f388473bc2c-agordeev@linux.ibm.com> References: <20261002152055.3305184-1-hca@linux.ibm.com> <20261002152055.3305184-3-hca@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261002152055.3305184-3-hca@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDEzMDA0NiBTYWx0ZWRfXzvRdrmgg9hdb WiLPyg7rBMd7e4IH+o2wuP6FiimwSjMvIZPKldCw8aTYgtoCvWzgMuOFrEPXneOw+HctNihdQ/R q+A+JFrK1RLOExl2qa5PjisP4eYkOBf1RgJrNMLirgq87Ex3tcxW9R3j5rp+v108MHYQib4/H/m qDB5qFuZzwGhy4BmUoVxe3CwLGaVZIjvxwwnQYSLQpoOV589001wMPRB937Aex57Dujs/ta33Iu vjqywDpsYg3RAbu/jW+QI0sSHnxwFQspKlFRHv9l3VmovNqUxhFExOCjrCqfyjk8FKTHTKDISdW xu6Jq7YPhCmrPPoqf+UrR0d3J5YR+hxEkRh4kCRRUS8vDixGL6X2bI9wjvxQSLGKEyCTxzxk73S rYWfII3lxlcX23ICKW7omLK71WiaQtpk2wUR/J+opoMcZ5wom7w9RY84n/IpmrwILc5V/DNtsU+ nuKbsdMSfNh+/+87uZA== X-Proofpoint-Spam-Info: AW1haW4tMjYxMDEzMDA0NiBTYWx0ZWRfXxQmpI13cNuO/ YiIST6943wgeUJbse6b8ffw8Gj8n9RRDXuxcHpVJnW8JZpAXkJGQXCWgX9M5HC1Z+jGfd3WqLPp b6NNv1ZYaqcNdYI3D3665GfkoJvN26M= X-Proofpoint-ORIG-GUID: yGwdwn__FG5Aw5rXpLstx8_Eltm1t_xR X-Authority-Analysis: v=2.4 cv=a6KlZkSF c=1 sm=1 tr=0 ts=6ace1c36 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=kj9zAlcOel0A:10 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=CK1eOIlrFaIt_kM6disA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-GUID: yGwdwn__FG5Aw5rXpLstx8_Eltm1t_xR 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=2026-10-13_01,2026-10-09_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 malwarescore=0 spamscore=0 suspectscore=0 clxscore=1015 phishscore=0 priorityscore=1501 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610080000 definitions=main-2610130046 On Fri, Oct 02, 2026 at 05:20:55PM +0200, Heiko Carstens wrote: > In case of an invalid kernel stack copy the current CPU's lowcore to > stack_invalid_lowcore, so it is available to debug tools after a crash. > > The copy is helpful since the lowcore is modified e.g., when printing > messages before a dump is taken. Keep it as unmodified as possible and > as close to the event that caused register corruption. > > Signed-off-by: Heiko Carstens > --- > arch/s390/kernel/entry.S | 15 +++++++++++++++ > arch/s390/kernel/entry.h | 4 ++++ > arch/s390/kernel/traps.c | 6 ++++++ > 3 files changed, 25 insertions(+) Reviewed-by: Alexander Gordeev