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GET /api/1.1/patches/2233344/?format=api
{ "id": 2233344, "url": "http://patchwork.ozlabs.org/api/1.1/patches/2233344/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/a64fa7d86da51f78743bee26e16ae155c43016c7.1778057685.git.sayalip@linux.ibm.com/", "project": { "id": 2, "url": "http://patchwork.ozlabs.org/api/1.1/projects/2/?format=api", "name": "Linux PPC development", "link_name": "linuxppc-dev", "list_id": "linuxppc-dev.lists.ozlabs.org", "list_email": "linuxppc-dev@lists.ozlabs.org", "web_url": "https://github.com/linuxppc/wiki/wiki", "scm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git", "webscm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/" }, "msgid": "<a64fa7d86da51f78743bee26e16ae155c43016c7.1778057685.git.sayalip@linux.ibm.com>", "date": "2026-05-06T09:06:12", "name": "[1/3] powerpc/time: remove preempt_disable/enable from arch_irq_work_raise()", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "2aced1431e5289fb620380be41a97a7e989af0bd", "submitter": { "id": 92656, "url": "http://patchwork.ozlabs.org/api/1.1/people/92656/?format=api", "name": "Sayali Patil", "email": "sayalip@linux.ibm.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/a64fa7d86da51f78743bee26e16ae155c43016c7.1778057685.git.sayalip@linux.ibm.com/mbox/", "series": [ { "id": 502942, "url": "http://patchwork.ozlabs.org/api/1.1/series/502942/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=502942", "date": "2026-05-06T09:06:11", "name": "MCE robustness fixes and LKDTM powerpc enhancements", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/502942/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2233344/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2233344/checks/", "tags": {}, "headers": { "Return-Path": "\n <linuxppc-dev+bounces-20512-incoming=patchwork.ozlabs.org@lists.ozlabs.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256\n header.s=pp1 header.b=pBE9z69/;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org\n (client-ip=2404:9400:21b9:f100::1; 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lists.ozlabs.org;\n dmarc=pass (p=none dis=none) header.from=linux.ibm.com;\n dkim=pass (2048-bit key;\n unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256\n header.s=pp1 header.b=pBE9z69/; dkim-atps=neutral;\n spf=pass (client-ip=148.163.158.5; helo=mx0b-001b2d01.pphosted.com;\n envelope-from=sayalip@linux.ibm.com;\n receiver=lists.ozlabs.org) smtp.mailfrom=linux.ibm.com", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc\n\t:content-transfer-encoding:date:from:in-reply-to:message-id\n\t:mime-version:references:subject:to; s=pp1; bh=/OX0YmQ91ZbIkTbD/\n\t67h5JVJUVNat8e++/RtzSdSmVI=; b=pBE9z69/ryRd8l31HNoyCgtZzMk7rrAti\n\tQELE0LzqNG/EDjZzMbq47rnhQAZzYhw5cTKGhtTOpFhGO29nauIrojY7bO8BEY6j\n\tedqKVb1PkCv/ZUuwKv7uB5KKkk/IgLewzpaiPnXRd6yHRzly0rQWrkvDRZrJP65i\n\ta0zhGa3tV0c92lrPyjDC5lwh1ggKWKnqczHw7dmXYdQNvqHDlC6HxedqyCz2MKfN\n\tGEceHZADyC+DxZdCMayQFCkmTY7/CcqPS37z5Lz6s1g40XSPOyHAHU/ruZj9TrRp\n\t1yrVhP3nXRCnDXCuLPnotzDntJXXiFaXv0iQ5UkUCk9qSeZfj6hwA==", "From": "Sayali Patil <sayalip@linux.ibm.com>", "To": "linuxppc-dev@lists.ozlabs.org, maddy@linux.ibm.com", "Cc": "linux-kernel@vger.kernel.org, Ritesh Harjani <ritesh.list@gmail.com>,\n Mahesh Salgaonkar <mahesh@linux.ibm.com>, sshegde@linux.ibm.com,\n chleroy@kernel.org", "Subject": "[PATCH 1/3] powerpc/time: remove preempt_disable/enable from\n arch_irq_work_raise()", "Date": "Wed, 6 May 2026 14:36:12 +0530", "Message-ID": "\n <a64fa7d86da51f78743bee26e16ae155c43016c7.1778057685.git.sayalip@linux.ibm.com>", "X-Mailer": "git-send-email 2.52.0", "In-Reply-To": "<cover.1778057685.git.sayalip@linux.ibm.com>", "References": "<cover.1778057685.git.sayalip@linux.ibm.com>", "X-Mailing-List": "linuxppc-dev@lists.ozlabs.org", "List-Id": "<linuxppc-dev.lists.ozlabs.org>", "List-Help": "<mailto:linuxppc-dev+help@lists.ozlabs.org>", "List-Owner": "<mailto:linuxppc-dev+owner@lists.ozlabs.org>", "List-Post": "<mailto:linuxppc-dev@lists.ozlabs.org>", "List-Archive": "<https://lore.kernel.org/linuxppc-dev/>,\n <https://lists.ozlabs.org/pipermail/linuxppc-dev/>", "List-Subscribe": "<mailto:linuxppc-dev+subscribe@lists.ozlabs.org>,\n <mailto:linuxppc-dev+subscribe-digest@lists.ozlabs.org>,\n <mailto:linuxppc-dev+subscribe-nomail@lists.ozlabs.org>", "List-Unsubscribe": "<mailto:linuxppc-dev+unsubscribe@lists.ozlabs.org>", "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=XPQAjwhE c=1 sm=1 tr=0 ts=69fb0491 cx=c_pps\n a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17\n a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22\n a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=ES_PRLIWHEyu4WWh1w8A:9", "X-Proofpoint-ORIG-GUID": "3Wb57npoFTKTbM3wDPzFmvXjkmZgL2UQ", "X-Proofpoint-GUID": "dLKAQyOrL7NW9a9Ui_QOPVs6EZvcGSny", "X-Proofpoint-Spam-Details-Enc": "AW1haW4tMjYwNTA2MDA4OCBTYWx0ZWRfXzktigx1BSbPZ\n IHtLBu/QItIlVMumA4Qy+w3rweontkKbf461YJiWTk6ylknOPLa11FEnwbcSZR3V9WXlkEasQaH\n Fem+F+v9P7C04YfrngaSvsJ8kYeig0nCjfR88B4lM2uoiyDx6SaY/COEYTkKye2STS8lzla5wq5\n uD+kLosauHxIdpqPgdiVjhuIWs25QQx7pKJbOAg+m0YlMA9Sz8ovy3JNpQPhdN66OWkKtAv2Eqq\n NgJiD1HmrcI51L5pIHHWNGvyegTEKB+XzPqISi+Vws6qW5Mw6iFzjaN3cFtORhfDzUEX4juaB4a\n PmCn9AOVXcwm/ggx/tzxG6KV7K3xD128f2UI7gwYqhdLjBEn3ivo/FIUrWYpi2uhVEv/ul88OP8\n hdSCg2GjD26PJ3QlWxNvRQ5hvbBnmFhWh3unFuJiOL+cKeZuBDo3RudQ16jlvj+vKbSSKxObKJS\n Lup+/C+sIIOL9WpBwuQ==", "X-Proofpoint-Virus-Version": "vendor=baseguard\n engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49\n definitions=2026-05-05_03,2026-04-30_02,2025-10-01_01", "X-Proofpoint-Spam-Details": "rule=outbound_notspam policy=outbound score=0\n bulkscore=0 lowpriorityscore=0 suspectscore=0 adultscore=0 spamscore=0\n priorityscore=1501 impostorscore=0 phishscore=0 malwarescore=0 clxscore=1015\n classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0\n reason=mlx scancount=1 engine=8.22.0-2604200000 definitions=main-2605060088", "X-Spam-Status": "No, score=-0.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID,\n\tRCVD_IN_DNSWL_LOW,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,\n\tSPF_PASS autolearn=disabled version=4.0.1 OzLabs 8", "X-Spam-Checker-Version": "SpamAssassin 4.0.1 (2024-03-25) on lists.ozlabs.org" }, "content": "A kernel panic is observed when handling machine check exceptions from\nreal mode.\n\n BUG: Unable to handle kernel data access on read at 0xc00000006be21300\n Oops: Kernel access of bad area, sig: 11 [#1]\n NIP [c000000000029e40] arch_irq_work_raise+0x10/0x70\n LR [c00000000003ffc8] machine_check_queue_event+0xa8/0x150\n Call Trace:\n [c0000000179d3c70] [c00000000003ff64] machine_check_queue_event+0x44/0x150\n [c0000000179d3d30] [c0000000000084e0] machine_check_early_common+0x1f0/0x2c0\n\nThe crash occurs because arch_irq_work_raise() calls preempt_disable()\nfrom machine check exception (MCE) handlers running in real mode. In\nthis context, accessing the preempt_count can fault, leading to the panic.\n\nThe preempt_disable()/preempt_enable() pair in arch_irq_work_raise()\nwas originally added by commit 0fe1ac48bef0 (\"powerpc/perf_event: Fix\noops due to perf_event_do_pending call\") to avoid races while raising\nirq work from exception context.\n\nLater, commit 471ba0e686cb (\"irq_work: Do not raise an IPI when\nqueueing work on the local CPU\") added preemption protection in\nirq_work_queue() path, while commit 20b876918c06 (\"irq_work: Use per\ncpu atomics instead of regular atomics\") added equivalent\nprotection in irq_work_queue_on() before reaching arch_irq_work_raise():\n\n irq_work_queue() / irq_work_queue_on()\n -> preempt_disable()\n -> __irq_work_queue_local()\n -> irq_work_raise()\n -> arch_irq_work_raise()\n\nAs a result, callers other than mce_irq_work_raise() already execute\nwith preemption disabled, making the additional\npreempt_disable()/preempt_enable() pair in arch_irq_work_raise()\nredundant.\n\nRemove it to avoid accessing preempt_count from real mode context.\n\nFixes: cc15ff327569 (\"powerpc/mce: Avoid using irq_work_queue() in realmode\")\nSuggested-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>\nSigned-off-by: Sayali Patil <sayalip@linux.ibm.com>\n---\n arch/powerpc/kernel/time.c | 2 --\n 1 file changed, 2 deletions(-)", "diff": "diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c\nindex 4bbeb8644d3d..a99eb43f6ce9 100644\n--- a/arch/powerpc/kernel/time.c\n+++ b/arch/powerpc/kernel/time.c\n@@ -471,10 +471,8 @@ void arch_irq_work_raise(void)\n \t * which could get tangled up if we're messing with the same state\n \t * here.\n \t */\n-\tpreempt_disable();\n \tset_irq_work_pending_flag();\n \tset_dec(1);\n-\tpreempt_enable();\n }\n \n static void set_dec_or_work(u64 val)\n", "prefixes": [ "1/3" ] }