{"id":2233344,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2233344/?format=json","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=json","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":"","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=json","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=json","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 ","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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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 \nSigned-off-by: Sayali Patil \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"]}