From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 071BE2FABFC; Tue, 12 Aug 2025 18:54:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755024864; cv=none; b=OLHjugJDflNGTBmUXlPV2LEoz+jfHjXsDTOIRcF4MIAMPSQdCwyhLCgAmbowuMvHnNFAkrgaIH70C0piSpEqexuQKMmcpXHCTAiJaKJAoXiwm4Hg6n4eJCsGgK6RXPEgRfw9odecpX+L9AzrHUWMkPH59b5kta3NVWqL1obhaEM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755024864; c=relaxed/simple; bh=1XVmGCmElCiOPPIZXTlEMEeagWBGKRL0GUBV/3NKP2Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lemARlFtaW/Y6BMGvX/OznuNjT6974TYJCBoIp+Q9UP0pu5tCJefIEjkOrMLVIum+8nph9XHWpoiHDD0ucO+QydTRPLuD3cC8KGBbtjIsPCZ8MKBRg/8xmLlnMMIpywUhNmzZgO3bXCQivAFPEPxFZyeK8BbTaVi/VQH9qzqYH0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DLydht8+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DLydht8+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 65EF5C4CEF0; Tue, 12 Aug 2025 18:54:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755024863; bh=1XVmGCmElCiOPPIZXTlEMEeagWBGKRL0GUBV/3NKP2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DLydht8+ksHIGy6UGepaepMbWRNLdK3YzeNt/Iq+ptZcbxcZgZmJmj1LvRpE1dhMn KZOB4flerC6oPKZ7Bp+DzWEFIXP6q1JaD8+C0tjEFPTqNY/RfptsQ23tc5TovR5Oux Ma/T2VUq/ZgEtk+XsN1H5S0JxhIUdE65x8ElAj00= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chris Mason , Beata Michalska , "Peter Zijlstra (Intel)" , Linus Torvalds , Sasha Levin Subject: [PATCH 6.16 500/627] sched/psi: Fix psi_seq initialization Date: Tue, 12 Aug 2025 19:33:15 +0200 Message-ID: <20250812173447.140930304@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250812173419.303046420@linuxfoundation.org> References: <20250812173419.303046420@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra [ Upstream commit 99b773d720aeea1ef2170dce5fcfa80649e26b78 ] With the seqcount moved out of the group into a global psi_seq, re-initializing the seqcount on group creation is causing seqcount corruption. Fixes: 570c8efd5eb7 ("sched/psi: Optimize psi_group_change() cpu_clock() usage") Reported-by: Chris Mason Suggested-by: Beata Michalska Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- kernel/sched/psi.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 5f7c023c4cca..3f9f0a39e858 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -172,7 +172,7 @@ struct psi_group psi_system = { .pcpu = &system_group_pcpu, }; -static DEFINE_PER_CPU(seqcount_t, psi_seq); +static DEFINE_PER_CPU(seqcount_t, psi_seq) = SEQCNT_ZERO(psi_seq); static inline void psi_write_begin(int cpu) { @@ -200,11 +200,7 @@ static void poll_timer_fn(struct timer_list *t); static void group_init(struct psi_group *group) { - int cpu; - group->enabled = true; - for_each_possible_cpu(cpu) - seqcount_init(per_cpu_ptr(&psi_seq, cpu)); group->avg_last_update = sched_clock(); group->avg_next_update = group->avg_last_update + psi_period; mutex_init(&group->avgs_lock); -- 2.39.5