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 496722F3649; Tue, 17 Jun 2025 15:44:05 +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=1750175045; cv=none; b=PgxUEapI+MljqBkXRLsg9GgXrtr49SHVpJ4FZtlrjOOOG1nfxv8wBSYizz0Uvif9DLEEVoVyVW3uX3gtG2otLEZ6NPL7215utYD8vid+RUIXr7DAT/pS6q4ErEuH9mJd+viuN3YM2WXHO66xElTCZAtxtS3UR/AKC0Cs5CjroLU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750175045; c=relaxed/simple; bh=mEUnyeC/sZ818zDSvqVMdHpRv5ZoHK4QgJK6hlk5v+8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DTzKVkoTkMCzTvU92gVad8JlzW+0UVLy02Pc6c+NtOKQ75AHNhpvHDU2GTTCKaQWBxElRNVb+RkiOqPyU53lZ/q3FW/37DoIshaT2W6UAkzvhp4rnq05u+YB2uXK72DRLMshXta/5yulsE8boUkOGjpj6t8yM6HxN2uCoQlFc6w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=e5CppZHk; 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="e5CppZHk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF61EC4CEF0; Tue, 17 Jun 2025 15:44:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750175045; bh=mEUnyeC/sZ818zDSvqVMdHpRv5ZoHK4QgJK6hlk5v+8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e5CppZHkVZsVtZZCv7hYrmP3rFwX4kQs+HOFuESWe4oBZa5+nP4Vxi9SgLlAjltVp a5oj0wFKVyL3mEyyxaY3ItSM9rNzyKvmV3WoT/UfCmAlYL5zico3H6zDT2EKjPPTAk sHZVWKU4TISm/QpnfjmQ1vixSf27E1mWyFYBT4YA= 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 6.15 044/780] rcu/cpu_stall_cputime: fix the hardirq count for x86 architecture Date: Tue, 17 Jun 2025 17:15:52 +0200 Message-ID: <20250617152453.288904792@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250617152451.485330293@linuxfoundation.org> References: <20250617152451.485330293@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-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 659f83e710486..80b10893b5038 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -801,6 +801,10 @@ 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 @@ -936,9 +940,9 @@ 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 925fcdad5dea2..56b21219442b6 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -435,8 +435,8 @@ 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