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Fri, 6 Nov 2026 10:43:09 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 6 Nov 2026 10:43:09 +0000 (GMT) From: Mikhail Zaslonko To: Andrew Morton , Baoquan He Cc: Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Dave Young , Jiri Bohac , David Hildenbrand , Usama Arif , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] kdump: Give crashkernel CMA areas unique names Date: Fri, 6 Nov 2026 11:43:09 +0100 Message-ID: <20261106104309.3669583-1-zaslonko@linux.ibm.com> X-Mailer: git-send-email 2.53.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=LKHz05W9 c=1 sm=1 tr=0 ts=6aedaf42 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=zJRp6_cAMcgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=hR5eV2nCcz1Zz8vUuPwA:9 X-Proofpoint-GUID: CVJwi85HMVi4di98wVuO7BMLHM0mh7Rm X-Proofpoint-Spam-Info: AW1haW4tMjYxMTA2MDA0MCBTYWx0ZWRfX46OaJdwxmACt eJ0su/177/KowBAIMk7OoWdwirMtqYrcLXeRoqSw7RAD5eyoCk8yh/wwbBr77pE5rpQXZSvawB7 892uXMCU08MJVU79OyYVCtYtwag7kBg= X-Proofpoint-ORIG-GUID: CVJwi85HMVi4di98wVuO7BMLHM0mh7Rm X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMTA2MDA0MCBTYWx0ZWRfX80Zh2xVqO8L8 D+Reh8yqrxwfG5pOc3L0Bwk2oYeYPnyyDec3iAiVYVSh6jG25dMlrtybpM8rLpHWeA/h1W2u6Ow BjdrIvJ7F/XJZcAt+Y+FNaDBZW2qjeMTdxChMZlDzx4Pd4NCsffzHeKP8Y73+u4GvO69bG8Lbv5 GhwygeZQRGGRkUkGmCiLHw9hdXRJpR1qfXCukeE06hKF3z0zZtNSKfNF6ZE8WL7aI5ksJwJbxEr myQmewboZPFPGjPQrBWY+xAZPOaCqd2aS5mO7+8mGZILcE9DCiCvDtPWWoesvlvJE28pdk44MT6 vj1QVwMC7RszoQyZ8MPc20F1fambmUPHdyv95efjGMO5BLV2Wcp7ZIdMtKCB1kaeTObHpAT5VeJ cbiYiApP49Z3WGbzDMVY8EwXTF7ouxQVRNBWDqBasMRaVtj//rISaUX5Ld/TaYECQbZz1D67RjK /nMwsxAnCLxXwOUk59g== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-11-06_02,2026-11-04_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 spamscore=0 suspectscore=0 lowpriorityscore=0 impostorscore=0 priorityscore=1501 bulkscore=0 clxscore=1011 malwarescore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2611040001 definitions=main-2611060040 reserve_crashkernel_cma() names every CMA area it reserves "crashkernel". If the requested size can't be reserved in one piece, it falls back to several smaller areas, all with the same name. With CONFIG_CMA_SYSFS, cma_sysfs_init() then fails to create the second directory: sysfs: cannot create duplicate filename '/kernel/mm/cma/crashkernel' and the error path removes the sysfs entries of all CMA areas. With CONFIG_CMA_DEBUGFS, debugfs refuses the duplicate directories as well: debugfs: 'crashkernel' already exists in 'cma' so only the first area shows up in debugfs. Keep the name of the first area and add the index to the others: crashkernel, crashkernel1, crashkernel2, ... Fixes: ab475510e042 ("kdump: implement reserve_crashkernel_cma") Signed-off-by: Mikhail Zaslonko --- Found while adding crashkernel CMA support for s390. kernel/crash_reserve.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c index eee37a11380c..e58318b1e092 100644 --- a/kernel/crash_reserve.c +++ b/kernel/crash_reserve.c @@ -483,10 +483,16 @@ void __init reserve_crashkernel_cma(unsigned long long cma_size) while (cma_size > reserved_size && crashk_cma_cnt < CRASHKERNEL_CMA_RANGES_MAX) { + char name[CMA_MAX_NAME]; struct cma *res; + /* CMA area names show up in sysfs and debugfs, keep them unique */ + if (crashk_cma_cnt) + snprintf(name, sizeof(name), "crashkernel%d", crashk_cma_cnt); + else + strscpy(name, "crashkernel"); if (cma_declare_contiguous(0, request_size, 0, 0, 0, false, - "crashkernel", &res)) { + name, &res)) { /* reservation failed, try half-sized blocks */ if (request_size <= PAGE_SIZE) break; base-commit: f66469d9905b39d2c260a15d7d6db450f4db67c1 -- 2.55.0