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 630FD221F1F; Tue, 17 Jun 2025 15:35:29 +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=1750174529; cv=none; b=D/NTctEOi6GWUlPsGHM+zOAO7mwh1KNLGCFiylg2DugK5qobYNfYyAUWR0Xh6GdKtjBDDMsg5vLdzNbyW4djew5e9YzebUyWTO3ttweJGYx+VeesqN1zS8tL3qt3i0+1arhPMQ4oGhtGfBdEhAyG1dEUlnaK9490Z4dT5JFIRp8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750174529; c=relaxed/simple; bh=n1ddIwVP5OQGyNOs/B4Ho+vXcNoEIRxeVdCOxRD6olc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ah7d+lW2MLmoZOEjHahGszFVVAi7/EQw1SHP794IYePWIlH3dP9wnIIAZbrp7+A+GrKSgIjHdyYEL7ERPdegN/xzenbt4K85/mn33JKAl68hyNSjjBMtl756gMfVKVyU40RygRoFcZvIgtTlwpgcD/c+Vr0rhwp3ugHEQ+eWAcY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=oWhoUqJ9; 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="oWhoUqJ9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6E8FC4CEE3; Tue, 17 Jun 2025 15:35:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750174529; bh=n1ddIwVP5OQGyNOs/B4Ho+vXcNoEIRxeVdCOxRD6olc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oWhoUqJ9fvPkK15pW0gRfHdamJMLCJBuMj3duD+wlSdkioQIWMjvjXf7FVZ4sPl8i OYeCPT2E+LfBbirfj+wVsYqVJOXOjqyXxF2kufd1rGJU0azagRPSqTbograNz0lUQ/ qTrDpiwTRGtZXq6525KN7M1mDWsFx4XhD6wujEZM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, kernel test robot , Yongliang Gao , Neeraj Upadhyay , Boqun Feng , Joel Fernandes , Sasha Levin Subject: [PATCH 6.12 030/512] rcu/cpu_stall_cputime: fix the hardirq count for x86 architecture Date: Tue, 17 Jun 2025 17:19:56 +0200 Message-ID: <20250617152420.780669857@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250617152419.512865572@linuxfoundation.org> References: <20250617152419.512865572@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yongliang Gao [ Upstream commit da6b85598af30e9fec34d82882d7e1e39f3da769 ] When counting the number of hardirqs in the x86 architecture, it is essential to add arch_irq_stat_cpu to ensure accuracy. For example, a CPU loop within the rcu_read_lock function. Before: [ 70.910184] rcu: INFO: rcu_preempt self-detected stall on CPU [ 70.910436] rcu: 3-....: (4999 ticks this GP) idle=*** [ 70.910711] rcu: hardirqs softirqs csw/system [ 70.910870] rcu: number: 0 657 0 [ 70.911024] rcu: cputime: 0 0 2498 ==> 2498(ms) [ 70.911278] rcu: (t=5001 jiffies g=3677 q=29 ncpus=8) After: [ 68.046132] rcu: INFO: rcu_preempt self-detected stall on CPU [ 68.046354] rcu: 2-....: (4999 ticks this GP) idle=*** [ 68.046628] rcu: hardirqs softirqs csw/system [ 68.046793] rcu: number: 2498 663 0 [ 68.046951] rcu: cputime: 0 0 2496 ==> 2496(ms) [ 68.047244] rcu: (t=5000 jiffies g=3825 q=4 ncpus=8) Fixes: be42f00b73a0 ("rcu: Add RCU stall diagnosis information") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202501090842.SfI6QPGS-lkp@intel.com/ Signed-off-by: Yongliang Gao Reviewed-by: Neeraj Upadhyay Link: https://lore.kernel.org/r/20250216084109.3109837-1-leonylgao@gmail.com Signed-off-by: Boqun Feng Signed-off-by: Joel Fernandes Signed-off-by: Sasha Levin --- kernel/rcu/tree.c | 10 +++++++--- kernel/rcu/tree.h | 2 +- kernel/rcu/tree_stall.h | 4 ++-- 3 files changed, 10 insertions(+), 6 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 4ed8632195217..cefa831c8cb32 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -802,6 +802,10 @@ static int rcu_watching_snap_save(struct rcu_data *rdp) return 0; } +#ifndef arch_irq_stat_cpu +#define arch_irq_stat_cpu(cpu) 0 +#endif + /* * Returns positive if the specified CPU has passed through a quiescent state * by virtue of being in or having passed through an dynticks idle state since @@ -937,9 +941,9 @@ static int rcu_watching_snap_recheck(struct rcu_data *rdp) rsrp->cputime_irq = kcpustat_field(kcsp, CPUTIME_IRQ, cpu); rsrp->cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu); rsrp->cputime_system = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu); - rsrp->nr_hardirqs = kstat_cpu_irqs_sum(rdp->cpu); - rsrp->nr_softirqs = kstat_cpu_softirqs_sum(rdp->cpu); - rsrp->nr_csw = nr_context_switches_cpu(rdp->cpu); + rsrp->nr_hardirqs = kstat_cpu_irqs_sum(cpu) + arch_irq_stat_cpu(cpu); + rsrp->nr_softirqs = kstat_cpu_softirqs_sum(cpu); + rsrp->nr_csw = nr_context_switches_cpu(cpu); rsrp->jiffies = jiffies; rsrp->gp_seq = rdp->gp_seq; } diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index a9a811d9d7a37..1bba2225e7448 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -168,7 +168,7 @@ struct rcu_snap_record { u64 cputime_irq; /* Accumulated cputime of hard irqs */ u64 cputime_softirq;/* Accumulated cputime of soft irqs */ u64 cputime_system; /* Accumulated cputime of kernel tasks */ - unsigned long nr_hardirqs; /* Accumulated number of hard irqs */ + u64 nr_hardirqs; /* Accumulated number of hard irqs */ unsigned int nr_softirqs; /* Accumulated number of soft irqs */ unsigned long long nr_csw; /* Accumulated number of task switches */ unsigned long jiffies; /* Track jiffies value */ diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 4432db6d0b99b..4d524a2212a8d 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -457,8 +457,8 @@ static void print_cpu_stat_info(int cpu) rsr.cputime_system = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu); pr_err("\t hardirqs softirqs csw/system\n"); - pr_err("\t number: %8ld %10d %12lld\n", - kstat_cpu_irqs_sum(cpu) - rsrp->nr_hardirqs, + pr_err("\t number: %8lld %10d %12lld\n", + kstat_cpu_irqs_sum(cpu) + arch_irq_stat_cpu(cpu) - rsrp->nr_hardirqs, kstat_cpu_softirqs_sum(cpu) - rsrp->nr_softirqs, nr_context_switches_cpu(cpu) - rsrp->nr_csw); pr_err("\tcputime: %8lld %10lld %12lld ==> %d(ms)\n", -- 2.39.5