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 C90FD4749F5; Tue, 4 Aug 2026 16:25:01 +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=1785860703; cv=none; b=B7A9eytJMXwKcHdtPi2sGl1iN5Pj7fFxlLU8u+pXGemfHMF4AobhD/HgcXVKYg67gSj7HKCiilE4E+C6GyGCegt85bUN0UJctM0R6pvfvlH8rVP9UPCmKsE1xTxUZG5WWEHsoilN8S4ezXdxKthIqdX3RQRvvZSt1cUT3wbD2ls= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785860703; c=relaxed/simple; bh=AtBaY1l3zkB1C+GK3FFBxpFxscFH0k+1+qnixDYfNM4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oK5M908hMeLW5M12wc9M/6USL+KkVfFmvBc32kRZsYgwKgoy+Cj9ztoO637HCuvz5pnmj8GmKzhB0GqkbqCjG2eL6Rh9ROIUdzQoJxC19Ol5ln621lxTnG1+QCBzlvGjG15RLweOLzi/stgFwPE3BtkSzIcGR9ohEzGpiEqaUfU= 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=JFNbSRBp; 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="JFNbSRBp" 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 674Flxp01341042; Tue, 4 Aug 2026 16:24:59 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=ugi7gyUJOirIDtK2r 4gU9u4w8jmpqJ4kMD7n4Mu2s/w=; b=JFNbSRBp3IMbCHGt1DadYOmjfVg1d5MGN Z3vduqs/c23VD1TsOIG/XHnHX+CxDQr9oPaHXqjzvx3QCHdDeo5s07ASPYOnj2cC vQ8MgbzwnZa+oZuXE2wa3g3aTShKlbEKS/HSRPyq5p8Wzi8psIgcdDh9tkAD5ia1 cEi9k1/GnjK95vanzznFQ8bCEHlB+AhU0f61CxtJVnzXGdvBQNJwR7JHmEMsqfCT oh9cwVVtD12bEz1K0nIlIo37Ny5iw2sx/n9sSS3ea85prJ85QMbamWeHthH75FxY q3bteUf1X7jCub1FqhemcxOfNJkox5euiXb48MS7SuiCt2HxmPscw== Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4fs8eupb9r-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 04 Aug 2026 16:24:58 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 674GBTQK007712; Tue, 4 Aug 2026 16:24:58 GMT Received: from smtprelay03.dal12v.mail.ibm.com ([172.16.1.5]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 4fsu4qjv68-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 04 Aug 2026 16:24:58 +0000 (GMT) Received: from smtpav02.wdc07v.mail.ibm.com (smtpav02.wdc07v.mail.ibm.com [10.39.53.229]) by smtprelay03.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 674GOvR715467046 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 4 Aug 2026 16:24:57 GMT Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F17ED5805C; Tue, 4 Aug 2026 16:24:56 +0000 (GMT) Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B56185805B; Tue, 4 Aug 2026 16:24:54 +0000 (GMT) Received: from b35lp69.lnxne.boe (unknown [9.87.84.240]) by smtpav02.wdc07v.mail.ibm.com (Postfix) with ESMTP; Tue, 4 Aug 2026 16:24:54 +0000 (GMT) From: Christian Borntraeger To: KVM Cc: Christian Borntraeger , Janosch Frank , David Hildenbrand , linux-s390 , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Sven Schnelle , Matthew Rosato , Douglas Freimuth Subject: [PATCH v2 7/7] KVM: s390: Free guest debug data on vcpu destroy Date: Tue, 4 Aug 2026 18:24:35 +0200 Message-ID: <20260804162435.28617-8-borntraeger@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260804162435.28617-1-borntraeger@linux.ibm.com> References: <20260804162435.28617-1-borntraeger@linux.ibm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: MBjyLTqYc3EDzladuekXvXUwveVU6gg8 X-Proofpoint-Spam-Info: AW1haW4tMjYwODA0MDEzMSBTYWx0ZWRfXxEoztewAQUiJ K3jGZEzQ4RWtS7LMvammuJtcG3CQ8ztnf0FlTTjfkA24krLPO3zC/kBNjp5MgV76PflJlOFJD61 9cGxdeYpGRqcpZK0EphDMCV63Iu/DKo= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODA0MDEzMSBTYWx0ZWRfX2MR6IfsBoGd5 nX7ylD4sd1zcsNysgemIiAZPwGtpBR3V+xP+4cO4LHz4SdwR/zujkTdBidJ9KG0Mjxpyh/fI+Hk no9URAlTRolSw9l2G7MVFQVciGBaPhJfZd6F7+pBUqQx/H8WOEPMlqbDhLR2Hbyyi5feouYgNRS yMUjUUniNiyAshCiTlOm0Gcp4UPNcgNXxXMuXEU1IFWQ5oyskgKuI476bZEGBBEQQgH87/g6nXv se5zjurWYA/DMiOX5qlNTCDgEvaC5r84eyO+RpkV2a7kq/ziZB6Y4ACsVa/KfijwQrgGGhZoTWq a8trHiZce1Iezu55eIvFm2oBN+1JXSQzOfymPV6z0DN+cuShJ8qHrHOAmAP17l1QrGOYXEq/m5s VWucQvys7oPJX9am8zKsW5Yw/RxFsfFZQA06BYnYjdSI3LWieLpodk6u64iSFWpqEmcebZVPt3F ruV516kOfWh/8vZHCyQ== X-Proofpoint-GUID: MBjyLTqYc3EDzladuekXvXUwveVU6gg8 X-Authority-Analysis: v=2.4 cv=KfzidwYD c=1 sm=1 tr=0 ts=6a72125b cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=FN5RJEE1uaSDo9arrcAA:9 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=2026-08-04_03,2026-08-04_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 bulkscore=0 impostorscore=0 suspectscore=0 malwarescore=0 adultscore=0 clxscore=1015 priorityscore=1501 phishscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608040131 kvm_s390_clear_bp_data() is only called from kvm_arch_vcpu_ioctl_set_guest_debug(), i.e. when user space changes or disables debugging. A vCPU that is destroyed while hardware breakpoints are still armed - the normal case when the VMM just exits or crashes - leaks hw_bp_info, hw_wp_info and all old_data buffers, since generic KVM frees the vCPU right after kvm_arch_vcpu_destroy(). That is bounded by MAX_BP_COUNT entries, so roughly 8 KiB per vCPU, but it is unbounded over VM lifetimes. The allocations are GFP_KERNEL_ACCOUNT, so the charge also outlives the exiting process and pins dying memcgs. Fix by clearing the debug data on vCPU destruction. Calling it unconditionally is fine: struct kvm_vcpu is zero allocated, so for a vCPU that never enabled debugging the counters are 0 and the pointers NULL. Fixes: 27291e2165b6 ("KVM: s390: hardware support for guest debugging") Cc: stable@vger.kernel.org Signed-off-by: Christian Borntraeger --- arch/s390/kvm/kvm-s390.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index e0548926dc49..ccbdb109e22c 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3409,6 +3409,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) trace_kvm_s390_destroy_vcpu(vcpu->vcpu_id); kvm_s390_clear_local_irqs(vcpu); kvm_clear_async_pf_completion_queue(vcpu); + kvm_s390_clear_bp_data(vcpu); if (!kvm_is_ucontrol(vcpu->kvm)) sca_del_vcpu(vcpu); kvm_s390_update_topology_change_report(vcpu->kvm, 1); -- 2.53.0