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Wed, 03 Jun 2026 06:27:57 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 6536RrO745089106 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 3 Jun 2026 06:27:53 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C2FDD20043; Wed, 3 Jun 2026 06:27:53 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 65CCD20040; Wed, 3 Jun 2026 06:27:50 +0000 (GMT) Received: from aboo.ibm.com.com (unknown [9.39.24.39]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 3 Jun 2026 06:27:50 +0000 (GMT) From: Aboorva Devarajan To: Madhavan Srinivasan , linuxppc-dev@lists.ozlabs.org Cc: Athira Rajeev , Aboorva Devarajan , Christophe Leroy , linux-kernel@vger.kernel.org, Sourabh Jain , Ritesh Harjani , Shrikanth Hegde Subject: [PATCH v2 0/3] powerpc: fix preempt_count imbalances in perf and kexec paths Date: Wed, 3 Jun 2026 11:57:40 +0530 Message-ID: <20260603062743.1152253-1-aboorvad@linux.ibm.com> X-Mailer: git-send-email 2.54.0 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=Zt3d7d7G c=1 sm=1 tr=0 ts=6a1fc96e cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=EHRFYB8xNeBlr5IdY6MA:9 X-Proofpoint-GUID: Tkkwab5r0hhCwwOAkKCB6xIHKnMW8LEI X-Proofpoint-ORIG-GUID: fYOsCkLXsSYfDrmSSXsLGwlgzP_21SqN X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjAzMDA1NiBTYWx0ZWRfX6C4Ap57hfJ42 OykgRKSgyfIhhSrpFV/SZ4FwLg/LbNwVXuJbNE/A//Se9z01RpyKJuNF3qn0R1F+zy6b3EkdEko iq8itIudR7TRfm+VlNsL7wT+0QdtZiHCm55L1atbaJS8NKAmyi0SNiQn8/NukVRQNbFsLDCq8X4 Zyp3cFAh8f23j7LxRodWFaz+uWkFnFIQGaI4UFBCIjuhlXdNkjSQodRYuyM92IP3jWbCcVjNRwa 6yYpENP6/qwP6AhAb4OBkw+gN+mPOmoH+xFaa7d7itoc9pbUHGpH+/DRbj/l7eQYQmABr5/wrrB XSxtXtAhHOuAIKvyhzbsBMH2FTr4YJGHofAZW/SAE3BPoPKvQqpBCXSiDX2ybCVsAxqiqlUHS8g 1WXxWewp2vfsrsYM5BByZfvvGsccwrw+u2iqDafFFBbNzCdLxlQ/xwsMAWqU3Pg22XwrNN2IESC RYnldTs2Uo0OrpFoC9g== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-03_02,2026-05-28_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 suspectscore=0 priorityscore=1501 bulkscore=0 clxscore=1015 phishscore=0 spamscore=0 malwarescore=0 adultscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605210000 definitions=main-2606030056 Hi all, This patch series fixes some minor preempt_count bookkeeping issues in arch/powerpc/ found during a preemption leak audit prompted by the lazy/full preemption model changes. These are get_cpu/put_cpu and get_cpu_var/put_cpu_var pairing errors that leave preempt_count incorrectly elevated or underflowed. v1: https://lore.kernel.org/all/20260518050855.1147242-1-aboorvad@linux.ibm.com/ v1 -> v2: - Patch 1 (fsl_emb_pmu_del): no functional change; picked up Shrikanth's Reviewed-by. - Patch 2 (pnv_kexec_wait_secondaries_down): per Shrikanth's review, use smp_processor_id() instead of raw_smp_processor_id(). The kexec/ crash teardown path runs with IRQs disabled so it is safe. - Patch 3 (kexec_prepare_cpus): per Shrikanth's review, dropped the approach of passing the cpu id through kexec_prepare_cpus_wait() as a parameter. kexec_prepare_cpus() already runs local_irq_disable()/ hard_irq_disable() before the wait, so get_cpu()/put_cpu() is unnecessary: just read the cpu id in kexec_prepare_cpus_wait() and drop the trailing put_cpu(). This keeps the function signature unchanged. smp_processor_id() is used here too, consistent with patch 2. Testing: - Patch 1: compile-tested only (ppc64e_defconfig + CONFIG_FSL_EMB_PERFMON); no e500/fsl_emb hardware to runtime-test so far. - Patches 2 and 3: kexec boot-tested on PowerNV (powernv_defconfig) and pseries (pseries_defconfig). Please let me know your comments. Thanks, Aboorva Aboorva Devarajan (3): powerpc/perf: fix preempt count underflow in fsl_emb_pmu_del powerpc/powernv: fix preempt count leak in pnv_kexec_wait_secondaries_down powerpc/kexec: fix double get_cpu() imbalance in kexec_prepare_cpus arch/powerpc/kexec/core_64.c | 4 +--- arch/powerpc/perf/core-fsl-emb.c | 3 ++- arch/powerpc/platforms/powernv/setup.c | 2 +- 3 files changed, 4 insertions(+), 5 deletions(-) -- 2.54.0