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Mon, 18 May 2026 08:08:48 +0000 (GMT) Received: from [9.123.5.233] (unknown [9.123.5.233]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 18 May 2026 08:08:48 +0000 (GMT) Message-ID: <0c6d2855-61df-4fd2-bede-0c204f4fd2b1@linux.ibm.com> Date: Mon, 18 May 2026 13:38:33 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/3] powerpc: fix preempt_count imbalances in perf and kexec paths To: Aboorva Devarajan , Madhavan Srinivasan , linuxppc-dev@lists.ozlabs.org Cc: Athira Rajeev , Christophe Leroy , linux-kernel@vger.kernel.org, Sourabh Jain , Ritesh Harjani References: <20260518050855.1147242-1-aboorvad@linux.ibm.com> Content-Language: en-US From: Shrikanth Hegde In-Reply-To: <20260518050855.1147242-1-aboorvad@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTE4MDA3NyBTYWx0ZWRfX6UdJrj9VYHY8 gfvU4X9yCmo0C73pXUsfo3Gm7F/y5O2hnnaFz87x2ZP/5UKzt44LI/mHxIKOo4LZmorShvGaLhm VyntXw2plOkIs8UDJFurTfgMgKVlFHqnrq/pt8/Ixdx1wk++Z1s+jM4v0jTqxha9VTYeelbhUh9 4ALUu0hnrq146Dmx22ODuUKql3nuXE+KSto6knZYJQATOK1gb+aDwUrSHE+NKsaIMw42g7qpXMU c36kmpB8Bsq4+RUsLnd70fFO3bou05fxm3HCfsL3lkO6KfkmMVgQpLUuqKo9lHRk9jIrizFMepy NyO5/uEHzjFhXbIk7FY/kGwWa/jO1FcX44ORdqbbtFFnroPgkawSPbeigzWkEB93y8ClEUM5THm n7WCwXytsqUaEuqwncT5kKSYEABsYQnNCvlqMnYuknR7wHN1+c787jSSWQ3gxojADG7XnvQ3vBw 0CytiuhQSqxjmlFxT2A== X-Proofpoint-GUID: XgjLBzZJ9ym1LC6G4bg5mxyPOFdSUTys X-Proofpoint-ORIG-GUID: nc6fjzRy3tsoti0Ti6ROiiorrgPE5ScS X-Authority-Analysis: v=2.4 cv=aYBRWxot c=1 sm=1 tr=0 ts=6a0ac916 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=Od8FwbK5lA2R0pW_jqYA:9 a=QEXdDO2ut3YA:10 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=2026-05-18_02,2026-05-15_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 adultscore=0 bulkscore=0 suspectscore=0 lowpriorityscore=0 clxscore=1015 spamscore=0 phishscore=0 priorityscore=1501 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605130000 definitions=main-2605180077 Hi Aboorva, On 5/18/26 10:38 AM, Aboorva Devarajan wrote: > 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. > Thanks for fixing some of these. while we do this, Can you fix these mismatch in preempt disable/enable in below files as well. 1. kernel/kprobes.c - kprobe_handler - Does disable, but doesn't enable in some return paths. A definite leak. 2. Maybe platforms/pseries/lpar.c and platforms/powernv/opal-tracepoints.c. In __trace_hcall_entry/exit. It maybe a very corner case, I don't see a big concern there. But it may be remotely possible. Need to evaluate whether it should be fixed or not.