From nobody Thu Sep 19 23:10:45 2024 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) (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 9B1AD770E6; Wed, 10 Jul 2024 06:13:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=60.244.123.138 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720592026; cv=none; b=YNTTlHZPZndF35KQV8XVkrcEGtsP+rRqIPF5t7kyELJVvQ2fDvrDAQutDYdOA5biXT7V8JWXEmjoNy23mPrGOIY5FHsdV6f/zuj/2HDRjMKiowbp6hRSzjLpherG5MMIn0C2WEebdRlXlBgTG+zW1WqNKVPzEqswrxH5uy2vK4M= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720592026; c=relaxed/simple; bh=SHbGtm4D0/iCitNfCWYTkWOmmCOtMKwROWXrGH5JhSE=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=u88TV23g/GihR58KpIhr2xDC/2oQwOZr5cfYiEZZUO1GrEGw6kFq/0utkicSVh3tgNLZBQ/EiP9sbERPeKOQN753uNTZwXZ4WBruELpMxTFcNTn2QtNskiLJrXoAeB6b6O1gCXsfZ6QM+w6mLF3DXbmUwVzxHb7KjBxq88VCn1M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mediatek.com; spf=pass smtp.mailfrom=mediatek.com; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b=uwSiQuKz; arc=none smtp.client-ip=60.244.123.138 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mediatek.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mediatek.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b="uwSiQuKz" X-UUID: 8b6d3ee83e8311efb5b96b43b535fdb4-20240710 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:MIME-Version:Message-ID:Date:Subject:CC:To:From; bh=d95Fo6b+G68P3kj0InKe88LIEg8qwPI54rMQxA2Bxok=; b=uwSiQuKzKKvip5XYmGbNlBFO1yvk3YW4x3ca1a1uu2voFf31r17fou63yWYqLWMnsohWZanjztaoPW/EAjP6c0pLTonXrwMBpBZNNoy1H6R0VEQnkb8PSB+IrcjL8nFturTG3k97ke+rYjaPYkHmigWq4qUaHPzZwNqPtAAO5Nw=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.40,REQID:04f5a53c-2f11-4d4c-adae-69db6a0018c7,IP:0,U RL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION: release,TS:0 X-CID-META: VersionHash:ba885a6,CLOUDID:66bc2ad5-0d68-4615-a20f-01d7bd41f0bb,B ulkID:nil,BulkQuantity:0,Recheck:0,SF:102,TC:nil,Content:0,EDM:-3,IP:nil,U RL:0,File:nil,RT:nil,Bulk:nil,QS:nil,BEC:nil,COL:0,OSI:0,OSA:0,AV:0,LES:1, SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0,ARC:0 X-CID-BVR: 0 X-CID-BAS: 0,_,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR X-UUID: 8b6d3ee83e8311efb5b96b43b535fdb4-20240710 Received: from mtkmbs14n2.mediatek.inc [(172.21.101.76)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 69503522; Wed, 10 Jul 2024 14:13:37 +0800 Received: from mtkmbs13n1.mediatek.inc (172.21.101.193) by MTKMBS14N1.mediatek.inc (172.21.101.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Wed, 10 Jul 2024 14:13:36 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkmbs13n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1118.26 via Frontend Transport; Wed, 10 Jul 2024 14:13:36 +0800 From: boy.wu To: Tejun Heo , Josef Bacik , Jens Axboe CC: Matthias Brugger , AngeloGioacchino Del Regno , Boris Burkov , , , , , , , Boy Wu Subject: [PATCH v2] blk-cgroup: Replace u64_sync with blkg_stat_lock for stats update Date: Wed, 10 Jul 2024 14:13:34 +0800 Message-ID: <20240710061334.1888-1-boy.wu@mediatek.com> X-Mailer: git-send-email 2.18.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-Product-Ver: SMEX-14.0.0.3152-9.1.1006-23728.005 X-TM-AS-Result: No-10--5.944900-8.000000 X-TMASE-MatchedRID: qLbn38WZ3sSZtBi01n3C9xafLXbshfogcx5k3wffojOHwGEm+CpYGTEG FjeZwyRUzogSaVJZzAL+luKvsi8YwoAemPpsxJ+FwCZxkTHxccn64i5lgawyBFSOymiJfTYXpR4 7IzBwt4ZOFu8ssjxG84NY9+fuummTlzyv7BXwQ5GeAiCmPx4NwBnUJ0Ek6yhjxEHRux+uk8jHUU +U0ACZwMVeAuLeAGwuBp7q3lDk3HqIXtzfrt5hBCumh16iMSocnqg/VrSZEiM= X-TM-AS-User-Approved-Sender: No X-TM-AS-User-Blocked-Sender: No X-TMASE-Result: 10--5.944900-8.000000 X-TMASE-Version: SMEX-14.0.0.3152-9.1.1006-23728.005 X-TM-SNTS-SMTP: 6E5764C31209FE9AC971FCE68D722875165DEF69209A65E7F099ADB9A84DB4E32000:8 X-MTK: N Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Boy Wu In 32bit SMP systems, if multiple CPUs call blkcg_print_stat, which may cause blkcg_fill_root_iostats to have a concurrent problem on the seqlock in u64_stats_update, which will cause a deadlock on u64_stats_fetch_begin in blkcg_print_one_stat. Thus use blkg_stat_lock to replace u64_sync. Fixes: ef45fe470e1e ("blk-cgroup: show global disk stats in root cgroup io.= stat") Signed-off-by: Boy Wu --- Change in v2: - update commit message - Remove u64_sync - Replace spin_lock_irq with guard statement - Replace blkg->q->queue_lock with blkg_stat_lock --- block/blk-cgroup.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 85b3b9051455..18b47ee1a640 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -952,7 +952,6 @@ static void blkcg_fill_root_iostats(void) struct blkcg_gq *blkg =3D bdev->bd_disk->queue->root_blkg; struct blkg_iostat tmp; int cpu; - unsigned long flags; =20 memset(&tmp, 0, sizeof(tmp)); for_each_possible_cpu(cpu) { @@ -974,9 +973,10 @@ static void blkcg_fill_root_iostats(void) cpu_dkstats->sectors[STAT_DISCARD] << 9; } =20 - flags =3D u64_stats_update_begin_irqsave(&blkg->iostat.sync); +#if BITS_PER_LONG =3D=3D 32 + guard(raw_spinlock_irqsave)(&blkg_stat_lock); +#endif blkg_iostat_set(&blkg->iostat.cur, &tmp); - u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags); } } =20 --=20 2.18.0