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 EC5DC3D1CB6; Mon, 4 May 2026 12:32:25 +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=1777897947; cv=none; b=VUlGnu6gVCKFi94FiH+2ucOXDwtth39ZGqCAvWT/WGqIFn/OQam0b4RGkIMeq+Q2foQx5+BoPd7XM2ukxHLjgmsGI6b2oiH4cpc6oahoppuz1aLYaYTv9SlfdXS3Svri/L5AFNJQbN9RhX/gVC77wW3hxeqT3rKKSpUqrBycoiw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777897947; c=relaxed/simple; bh=zClYkEjuH+1o3s1tWHhRymivFJ4xIHgsujjp9KWR2/A=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=cMzSfmbnky61tXXRM7YWAdiNJiN6SPVWUALaBRKQAuYKDSt2gj5iblDq9mL/BxGz/dbyS7QR2cPHGgCGgRPTsT+l5yKX/Uv2NdLCmm5njTYUTmoRDtqOYeNAhJCFA9KuPn3gp6w6nI/nMh26EXhA46S8weU7Nh9Fg5jumB6MbiM= 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=STvLhzQJ; 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="STvLhzQJ" Received: from pps.filterd (m0356516.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 644Albik2197452; Mon, 4 May 2026 12:31:58 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-type:date:from:message-id:mime-version:subject:to; s= pp1; bh=X/EqMnEIUCoNrn+IfIA+egTKhtM8AOXSpOvt0d40prc=; b=STvLhzQJ hHRyxBVGmhbzucIlzKecROZws/p131lSQ6G/u+eLePsXlNBpSgYXBLyyQtk8qU5K 3wUZyVqn/V/fk5qhy3dSPM46A3oCYfpRLFknevS66mL+6vC4HyVmaOxRi85gYGC1 0wYBNfEP56Te0bityvcnLul3TMvKyDnQ4/Uupkal2ZUjrbCTRnOVSfP3lA6XsZag ip1E7AZwqPt00y6PPNr3Yg/4i6R1dHHxXGBBk6nBUngEEyWa7odPOwnVJKwBdAh7 n+QWQ3ZkRxJVvng6oRGL1xYU8AhLoIQbRDNtqC4XmPfRUBpldgezdo/6yZfLfqDS f7WGiXuVY+QWtA== 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 4dw9w66qxm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 04 May 2026 12:31:57 +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 644COUsm018467; Mon, 4 May 2026 12:31:56 GMT Received: from smtprelay05.fra02v.mail.ibm.com ([9.218.2.225]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 4dwukq57fp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 04 May 2026 12:31:56 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay05.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 644CVtPo33751348 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 4 May 2026 12:31:55 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0764120040; Mon, 4 May 2026 12:31:55 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0F82D20043; Mon, 4 May 2026 12:31:54 +0000 (GMT) Received: from localhost (unknown [9.111.75.48]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTPS; Mon, 4 May 2026 12:31:53 +0000 (GMT) Date: Mon, 4 May 2026 14:31:52 +0200 From: Vasily Gorbik To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot Cc: Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , John Stultz , "Connor O'Brien" , Vineeth Pillai , Joel Fernandes , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 0/1] sched/core: Don't steal a proxy-exec donor Message-ID: 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 X-Patchwork-Bot: notify X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=XPQAjwhE c=1 sm=1 tr=0 ts=69f891be cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VwQbUJbxAAAA:8 a=1XWaLZrsAAAA:8 a=arff7jidZKLiyCVEszgA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: 5JfeAvuwdl2gq8g0MwSguNjwO36Ti8ze X-Proofpoint-GUID: PkVLviWoZbpKiLqcJfgF0_r_SpyfDAb6 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTA0MDEyOSBTYWx0ZWRfX3QyPfbZZmA6F SXXT5R7LPplpCdHtX/iNhk/6l/QLlZrFQA16z1X1AKBDZ+Z/S4hfmVrAiRW/zBjl3ZJGRkHmBq5 IgsONo7pzzN7eBcDRQI/lvg4RrsZ+nUhEJ2xGFdpdepBF8pV9w0FBak99SrLIHvZ2rg7fNqrnH5 CI5Nb99Yk1EQTm1Z5JcCt5nHXu0ynIPTjtWeOWhNhEIPG0Q5VNaJnaRGiZIp7nMXY5+Uyf8qO+j gC35kwVJo43ufle3qXYb8EIBhpwD3md3smvLMeutd7CLpQDiQuHleUPUiVjtR0C5AGjELb6/j3Q rbxh3EMNd27vU3sHO2ZlpXf8EzP9YPVHynZp7RqyX56Z59300RIVgSbudeYg2sUzcCignBKiKWy m/vpO2+aTOzz68vEcUu/ncFDtxMMhqlyl3MZHfHbWG4IxNdo7YDE/Ikd5dxyOH188Rv01rmZrU7 1EgbkuWjMn/abBj+F7A== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-05-04_04,2026-04-30_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 lowpriorityscore=0 suspectscore=0 adultscore=0 spamscore=0 priorityscore=1501 impostorscore=0 phishscore=0 malwarescore=0 clxscore=1011 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604200000 definitions=main-2605040129 Since sched-core-2026-04-13 pull s390 hits the following splats with defconfig. Running strace test suite "make -j$(nproc) check" on LPAR with 64 SMT-2 cores couple of times usually enough to trigger this. First WARN in put_prev_entity() on a strace task. The next pick on the same CPU typically WARNs again, and 60s later the system is in an rcu_sched stall [ 535.525203] WARNING: kernel/sched/fair.c:5788 at put_prev_entity+0xfe/0x170, CPU#26: grep/242219 [ 535.525212] Modules linked in: mptcp_diag xfrm_user xfrm_algo tcp_diag crypto_user inet_diag netlink_diag algif_hash af_alg dm_service_time nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables zfcp scsi_transport_fc s390_trng eadm_sch vfio_ccw mdev vfio_iommu_type1 vfio sch_fq_codel drm i2c_core loop dm_multipath drm_panel_orientation_quirks nfnetlink uvdevice diag288_wdt prng aes_s390 scsi_dh_rdac scsi_dh_emc scsi_dh_alua phmac_s390 paes_s390 crypto_engine pkey_cca pkey_ep11 zcrypt rng_core pkey_pckmo pkey autofs4 ecdsa_generic ecc sha512 [last unloaded: trace_printk] [ 535.525268] CPU: 26 UID: 1001 PID: 242219 Comm: grep Not tainted 7.1.0-20260426.rc0.git0.897d54018cc9.300.fc43.s390x+git #1 PREEMPTLAZY [ 535.525272] Hardware name: IBM 8561 T01 703 (LPAR) [ 535.525273] Krnl PSW : 0404e00180000000 0000033840f08482 (put_prev_entity+0x102/0x170) [ 535.525279] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 [ 535.525282] Krnl GPRS: 000000000000b8ee 0000000000000000 0000000000000000 0000000000000800 [ 535.525284] 0000000000000000 0000007cafc9c400 0000033840f084f0 00000003e5512b68 [ 535.525287] 00000003e5512b70 0000007cafc9c516 00000000dcd88400 00000001d3b8c900 [ 535.525289] 0000000000000000 00000001d3b8c800 0000033840f08474 000002b84839fbe0 [ 535.525297] Krnl Code: 0000033840f08474: e3b0a0580020 cg %r11,88(%r10) 0000033840f0847a: a784ffa5 brc 8,0000033840f083c4 *0000033840f0847e: af000000 mc 0,0 >0000033840f08482: e548a0580000 mvghi 88(%r10),0 0000033840f08488: eb9ff0a00004 lmg %r9,%r15,160(%r15) 0000033840f0848e: 07fe bcr 15,%r14 0000033840f08490: 47000700 bc 0,1792 0000033840f08494: c0e5ffffeb86 brasl %r14,0000033840f05ba0 [ 535.525367] Call Trace: [ 535.525372] [<0000033840f08482>] put_prev_entity+0x102/0x170 [ 535.525377] ([<0000033840f08474>] put_prev_entity+0xf4/0x170) [ 535.525381] [<0000033840f0852a>] put_prev_task_fair+0x3a/0x60 [ 535.525385] [<0000033840ef6e58>] pick_next_task+0x138/0xbd0 [ 535.525388] [<0000033841d364d0>] __schedule+0x180/0x850 [ 535.525391] [<0000033841d36bdc>] schedule+0x3c/0xc0 [ 535.525394] [<0000033841d32d10>] irqentry_exit+0x1c0/0x610 [ 535.525397] [<0000033841d32846>] do_ext_irq+0xe6/0x290 [ 535.525399] [<0000033841d41576>] ext_int_handler+0xc6/0xf0 [ 535.525402] Last Breaking-Event-Address: [ 535.525403] [<0000033840eff36a>] propagate_entity_load_avg+0x3a/0x490 [ 535.525407] ---[ end trace 0000000000000000 ]--- [ 535.525422] ------------[ cut here ]------------ [ 535.525424] WARNING: kernel/sched/fair.c:7022 at hrtick_start_fair+0x6c/0x80, CPU#26: swapper/26/0 [ 535.525428] Modules linked in: mptcp_diag xfrm_user xfrm_algo tcp_diag crypto_user inet_diag netlink_diag algif_hash af_alg dm_service_time nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables zfcp scsi_transport_fc s390_trng eadm_sch vfio_ccw mdev vfio_iommu_type1 vfio sch_fq_codel drm i2c_core loop dm_multipath drm_panel_orientation_quirks nfnetlink uvdevice diag288_wdt prng aes_s390 scsi_dh_rdac scsi_dh_emc scsi_dh_alua phmac_s390 paes_s390 crypto_engine pkey_cca pkey_ep11 zcrypt rng_core pkey_pckmo pkey autofs4 ecdsa_generic ecc sha512 [last unloaded: trace_printk] [ 535.525465] CPU: 26 UID: 0 PID: 0 Comm: swapper/26 Tainted: G W 7.1.0-20260426.rc0.git0.897d54018cc9.300.fc43.s390x+git #1 PREEMPTLAZY [ 535.525469] Tainted: [W]=WARN [ 535.525471] Hardware name: IBM 8561 T01 703 (LPAR) [ 535.525472] Krnl PSW : 0404e00180000000 0000033840ef9ac0 (hrtick_start_fair+0x70/0x80) [ 535.525476] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 [ 535.525479] Krnl GPRS: 0000007c00000001 00000003e5533800 00000003e5511800 00000001d3b8c800 [ 535.525482] 00000000000000d8 00000338429cd038 0000033840f19860 00000003e5511800 [ 535.525484] 00000001d3b8c800 000000000000003f 00000003e55127b0 00000001d3b8c948 [ 535.525486] 0000000000000000 0000000081992400 0000033840f0876a 000002b840e5bc48 [ 535.525492] Krnl Code: 0000033840ef9ab2: 47000700 bc 0,1792 0000033840ef9ab6: c0f4ffffd4dd brcl 15,0000033840ef4470 *0000033840ef9abc: af000000 mc 0,0 >0000033840ef9ac0: a7f4ffdc brc 15,0000033840ef9a78 0000033840ef9ac4: 0707 bcr 0,%r7 0000033840ef9ac6: 0707 bcr 0,%r7 0000033840ef9ac8: 0707 bcr 0,%r7 0000033840ef9aca: 0707 bcr 0,%r7 [ 535.525505] Call Trace: [ 535.525507] [<0000033840ef9ac0>] hrtick_start_fair+0x70/0x80 [ 535.525509] ([<0000033840f086fe>] set_next_task_fair+0x4e/0x230) [ 535.525513] [<0000033840ef6e76>] pick_next_task+0x156/0xbd0 [ 535.525515] [<0000033841d364d0>] __schedule+0x180/0x850 [ 535.525518] [<0000033841d36d16>] schedule_idle+0x36/0x60 [ 535.525520] [<0000033840f141ce>] do_idle+0x11e/0x160 [ 535.525523] [<0000033840f143e0>] cpu_startup_entry+0x40/0x50 [ 535.525526] [<0000033840e6f7c8>] smp_start_secondary+0x138/0x150 [ 535.525529] [<0000033841d40f72>] restart_int_handler+0x72/0x88 [ 535.525532] Last Breaking-Event-Address: [ 535.525533] [<0000033840ef9a72>] hrtick_start_fair+0x22/0x80 [ 535.525536] ---[ end trace 0000000000000000 ]--- [ 535.525549] ------------[ cut here ]------------ [ 535.525550] WARNING: kernel/sched/sched.h:1769 at set_next_entity+0x35a/0x370, CPU#26: swapper/26/0 [ 535.525555] Modules linked in: mptcp_diag xfrm_user xfrm_algo tcp_diag crypto_user inet_diag netlink_diag algif_hash af_alg dm_service_time nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables zfcp scsi_transport_fc s390_trng eadm_sch vfio_ccw mdev vfio_iommu_type1 vfio sch_fq_codel drm i2c_core loop dm_multipath drm_panel_orientation_quirks nfnetlink uvdevice diag288_wdt prng aes_s390 scsi_dh_rdac scsi_dh_emc scsi_dh_alua phmac_s390 paes_s390 crypto_engine pkey_cca pkey_ep11 zcrypt rng_core pkey_pckmo pkey autofs4 ecdsa_generic ecc sha512 [last unloaded: trace_printk] [ 535.525588] CPU: 26 UID: 0 PID: 0 Comm: swapper/26 Tainted: G W 7.1.0-20260426.rc0.git0.897d54018cc9.300.fc43.s390x+git #1 PREEMPTLAZY [ 535.525591] Tainted: [W]=WARN [ 535.525593] Hardware name: IBM 8561 T01 703 (LPAR) [ 535.525594] Krnl PSW : 0404d00180000000 0000033840f0395e (set_next_entity+0x35e/0x370) [ 535.525598] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 RI:0 EA:3 [ 535.525601] Krnl GPRS: 0000007caeee0479 07cafcf56a100000 0000000000000000 0000000000000000 [ 535.525604] 00000003e5445800 0000000000e15d28 0000033840f19860 00000003e5511800 [ 535.525606] 0000000000000001 0000000000000001 000000026ad0f400 00000001d3b8c900 [ 535.525608] 0000000000000000 0000000081992400 0000033840f036f6 000002b840e5bc00 [ 535.525613] Krnl Code: 0000033840f03952: b9e93090 sgrk %r9,%r0,%r3 0000033840f03956: a7f4fee7 brc 15,0000033840f03724 *0000033840f0395a: af000000 mc 0,0 >0000033840f0395e: a7f4fedb brc 15,0000033840f03714 0000033840f03962: 0707 bcr 0,%r7 0000033840f03964: 0707 bcr 0,%r7 0000033840f03966: 0707 bcr 0,%r7 0000033840f03968: 0707 bcr 0,%r7 [ 535.525626] Call Trace: [ 535.525627] [<0000033840f0395e>] set_next_entity+0x35e/0x370 [ 535.525630] ([<0000033840f036f6>] set_next_entity+0xf6/0x370) [ 535.525633] [<0000033840f086fe>] set_next_task_fair+0x4e/0x230 [ 535.525636] [<0000033840ef6e76>] pick_next_task+0x156/0xbd0 [ 535.525639] [<0000033841d364d0>] __schedule+0x180/0x850 [ 535.525642] [<0000033841d36d16>] schedule_idle+0x36/0x60 [ 535.525645] [<0000033840f141ce>] do_idle+0x11e/0x160 [ 535.525647] [<0000033840f143e0>] cpu_startup_entry+0x40/0x50 [ 535.525650] [<0000033840e6f7c8>] smp_start_secondary+0x138/0x150 [ 535.525652] [<0000033841d40f72>] restart_int_handler+0x72/0x88 [ 535.525655] Last Breaking-Event-Address: [ 535.525656] [<0000033840f03710>] set_next_entity+0x110/0x370 [ 535.525659] ---[ end trace 0000000000000000 ]--- [ 535.528235] ------------[ cut here ]------------ [ 535.528241] WARNING: kernel/sched/fair.c:5721 at set_next_entity+0x2c8/0x370, CPU#20: swapper/20/0 [ 535.528248] Modules linked in: mptcp_diag xfrm_user xfrm_algo tcp_diag crypto_user inet_diag netlink_diag algif_hash af_alg dm_service_time nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables zfcp scsi_transport_fc s390_trng eadm_sch vfio_ccw mdev vfio_iommu_type1 vfio sch_fq_codel drm i2c_core loop dm_multipath drm_panel_orientation_quirks nfnetlink uvdevice diag288_wdt prng aes_s390 scsi_dh_rdac scsi_dh_emc scsi_dh_alua phmac_s390 paes_s390 crypto_engine pkey_cca pkey_ep11 zcrypt rng_core pkey_pckmo pkey autofs4 ecdsa_generic ecc sha512 [last unloaded: trace_printk] [ 535.528291] CPU: 20 UID: 0 PID: 0 Comm: swapper/20 Tainted: G W 7.1.0-20260426.rc0.git0.897d54018cc9.300.fc43.s390x+git #1 PREEMPTLAZY [ 535.528295] Tainted: [W]=WARN [ 535.528296] Hardware name: IBM 8561 T01 703 (LPAR) [ 535.528297] Krnl PSW : 0404e00180000000 0000033840f038cc (set_next_entity+0x2cc/0x370) [ 535.528302] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 [ 535.528305] Krnl GPRS: 0000007caff854b2 00000001d3b8c900 0000000082cec900 00000003e5445800 [ 535.528308] 000000000000002e 00000000000f423f 0000033840f19860 00000003e5445800 [ 535.528310] 00000001d3b8c900 000000804f18b648 000000026ad0f400 00000001d3b8c900 [ 535.528312] 0000000000000000 000000008198c800 0000033840f03820 000002b840e2bc00 [ 535.528319] Krnl Code: 0000033840f038be: e310a0580002 ltg %r1,88(%r10) 0000033840f038c4: a784fece brc 8,0000033840f03660 *0000033840f038c8: af000000 mc 0,0 >0000033840f038cc: a7f4feca brc 15,0000033840f03660 0000033840f038d0: e310b4000002 ltg %r1,1024(%r11) 0000033840f038d6: a784ff09 brc 8,0000033840f036e8 0000033840f038da: 4140b400 la %r4,1024(%r11) 0000033840f038de: e330bf00ff71 lay %r3,-256(%r11) [ 535.528334] Call Trace: [ 535.528336] [<0000033840f038cc>] set_next_entity+0x2cc/0x370 [ 535.528339] ([<0000033840f037ac>] set_next_entity+0x1ac/0x370) [ 535.528342] [<0000033840f086fe>] set_next_task_fair+0x4e/0x230 [ 535.528345] [<0000033840ef6e76>] pick_next_task+0x156/0xbd0 [ 535.528348] [<0000033841d364d0>] __schedule+0x180/0x850 [ 535.528351] [<0000033841d36d16>] schedule_idle+0x36/0x60 [ 535.528354] [<0000033840f141ce>] do_idle+0x11e/0x160 [ 535.528356] [<0000033840f143e0>] cpu_startup_entry+0x40/0x50 [ 535.528359] [<0000033840e6f7c8>] smp_start_secondary+0x138/0x150 [ 535.528362] [<0000033841d40f72>] restart_int_handler+0x72/0x88 [ 535.528365] Last Breaking-Event-Address: [ 535.528366] [<0000033840f0365c>] set_next_entity+0x5c/0x370 [ 535.528369] ---[ end trace 0000000000000000 ]--- [ 595.527130] rcu: INFO: rcu_sched self-detected stall on CPU [ 595.527142] rcu: 7-...!: (47526 ticks this GP) idle=8f04/1/0x4000000000000000 softirq=56080/56080 fqs=0 [ 595.527175] rcu: (t=60000 jiffies g=232693 q=6273 ncpus=32) [ 595.527177] rcu: rcu_sched kthread timer wakeup didn't happen for 59996 jiffies! g232693 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 [ 595.527180] rcu: Possible timer handling issue on cpu=28 timer-softirq=1957 [ 595.527182] rcu: rcu_sched kthread starved for 60000 jiffies! g232693 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=28 [ 595.527184] rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. [ 595.527186] rcu: RCU grace-period kthread stack dump: Bisect pointed at commit e0ca8991b2de6 ("sched: Make class_schedulers avoid pushing current, and get rid of proxy_tag_curr()"), of the sched-core-2026-04-13 pull. But it only seems to make the corruption trigger easier, reverting it doesn't help. Applying "Proxy Execution fixes for v7.1-rc" [1] on top didn't help, nor did "Optimized Donor Migration for Proxy Execution" [2]. The problem goes away when sched_proxy_exec=0 or nosmt is used. Adding some debug code in deactivate_task() showed try_steal_cookie() calling it on src->donor right before the warning. try_steal_cookie() skips src->core_pick and src->curr but not src->donor. [1] https://lore.kernel.org/all/20260427183848.698551-1-jstultz@google.com/ [2] https://lore.kernel.org/all/20260422230659.903191-1-jstultz@google.com/ The following patch resolves the issue in my tests. Please consider it if it makes sense. Vasily Gorbik (1): sched/core: Don't steal a proxy-exec donor kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.53.0