From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0A1E1FB5173 for ; Mon, 6 Apr 2026 23:25:31 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4fqQRX6mdSz2xNT; Tue, 07 Apr 2026 09:25:28 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2607:f8b0:4864:20::1331" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1775517928; cv=none; b=TS44JN8eOuujM6vNtzlOSmP92QBOPfiAZt6+jrzMFtlQfnE+xziDkAqqUtYHVLlsHLvMnfLKyx6mEmnXxBo8r5lZ9pPMBzHV0cqeiWsj1bBNzqPCEGl+OMfQtPl2aq9FYYip+EhKSnKW7KjO1/pgXArAHLedmzYy6FBqjiA/O871w86widqamUwhqfWjtCNQtmlXGnFSx/HEgTDCGmmQjKFagwbjFuUmqU+5xX8OEcytSxcWSo2KrhgiG63eKbGpBfFb9yVSyg0gTP5cTobN8D2EFh35jOBY9eFrTQWRBOiyN51pmtgcPlnI87wREVTRRYEmKq/yD9Ho9yWOCsEqNw== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1775517928; c=relaxed/relaxed; bh=e+LsTmUaKDUP6TtbtpmsofePBR8TWMvjJHv9+/xi4nY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=TjOwBC4SQ2xwUJAEj2+10rD+CII5C/6ZgaOUnS1b/LE8MEKXvm+pcg4pTeKdDAAmFS2V6PbBpIht1F/NqtFOzzVCVSspTmB2NduDoiCdYE2PYAbJ1m8EC2mfod+FxHcpIwUIyM1Lad6gF4APHDsaOcpYEVd4kzWIkCz/zIsNeBvgDf7HDo4rpBZkV63kkb0iJ0zfnb3jp8UDx6M5i2DsIqR31hQulwRCOLyjfUoyfdHCWzqDOJ9nTBG7vsDclAI4nawgpr99c2TXQiwTFb1A+JhPTtAkNvDb1usQl/2M6CY0kzZFMMBhM7VbUetwO6M1mJGH7pYIE2zPf2v9UQwczA== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=chromium.org; dkim=pass (1024-bit key; unprotected) header.d=chromium.org header.i=@chromium.org header.a=rsa-sha256 header.s=google header.b=J51YEBaC; dkim-atps=neutral; spf=pass (client-ip=2607:f8b0:4864:20::1331; helo=mail-dy1-x1331.google.com; envelope-from=dianders@chromium.org; receiver=lists.ozlabs.org) smtp.mailfrom=chromium.org Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=chromium.org header.i=@chromium.org header.a=rsa-sha256 header.s=google header.b=J51YEBaC; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=chromium.org (client-ip=2607:f8b0:4864:20::1331; helo=mail-dy1-x1331.google.com; envelope-from=dianders@chromium.org; receiver=lists.ozlabs.org) Received: from mail-dy1-x1331.google.com (mail-dy1-x1331.google.com [IPv6:2607:f8b0:4864:20::1331]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4fqQRW0Lp3z2yfs for ; Tue, 07 Apr 2026 09:25:26 +1000 (AEST) Received: by mail-dy1-x1331.google.com with SMTP id 5a478bee46e88-2ce102afb0aso2630017eec.1 for ; Mon, 06 Apr 2026 16:25:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1775517923; x=1776122723; darn=lists.ozlabs.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=e+LsTmUaKDUP6TtbtpmsofePBR8TWMvjJHv9+/xi4nY=; b=J51YEBaCA+bUN38q3XXwMl21y97zWG5ODUEZhkKNQusDnDyZ323wmziB9eBSPBPGih LxsA74yXTRkqXHiCe8NunyctS9PeCoXYWchGeDgpjRbkcgnodIiEqXg8AJUhIHyzNIa8 yQtstMnnwR9jfHpMMUj2qHwroIcCbgmBeXY6I= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775517923; x=1776122723; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=e+LsTmUaKDUP6TtbtpmsofePBR8TWMvjJHv9+/xi4nY=; b=jWnwHUYkjTxAp/vJ40EM2uhD/t4BVlbWOmK1GQU/el+/M9hWQ4YWeeN9Rd84qFmyN6 D6Uxe4YP5JXKjAHhOpwvfHqDg/eYA6lK83PyqFuZDIrGnBpUFyBiwPKSOF+yWUVPQpDu 1OjHZ85W4R039qWN/ANLPzAcfSbyCoDsLae/FtSJ7j12VyW9WIyvzD7XY9gtf/lje4is UThM0wD/K2UIZEqRDgNwJcGrQj+TpJ1fQzMlI8fPK2vTOcsKyEuKvMkia35bNepSIlg4 4pTaQMFzUzXjEjGK5xdgG2JUNI2wasMkDYxLD2i2rAoK7plwjxbjRaInxtrO17sK/mKn iDxw== X-Forwarded-Encrypted: i=1; AJvYcCWYI1v4/8OZeavSEE/37KSRiKvWIUD1airuGap2ieVs0KAERrEL6WcA/8fdRqLyD8+9ewYla11mhPyHvqg=@lists.ozlabs.org X-Gm-Message-State: AOJu0YxwzJaPJwNLtdi1D700waWL5ztHODNc0zLtInqiYd8/YG5q8JSx q37WufNM+EQzVRJDaz7iEjtZWSWNrdKmbYgrzIXH35uA34a52+f7IjMWxBz/g/XWgQ== X-Gm-Gg: AeBDiesYO1Uajt175btCgC7VC0EphUTHVkSUU2PVZ7vsqM4l7kISCf3T5ONsx6ohotK INiahD2QLghJItURwCkkzgPJF4viNUO0OnVf7fHUz/Up7hzEJ6oAuYVJme5I5fy85pEwklblHD6 98POnLjkpTPPg7HgtCY2j9F/vnU6M1xtD0OKl9mzDhf8W/YK1hWXtF3NDLHDkPawL5a3XbF88bo sBYuWh0Yj4IF+Z02EFRTGIh+tnZNzMMLiq8NzfSoTIBNY0z079bpkG5bQTdIlzZziE8+wWPOexj vFl3iea3lgZNhPHdMKAtL/PMVJVgf3ipjYazAb4r/JFcrJ7AWqmTUrxROgPvErOG/hdYZKK2Uv+ av/0/LGB8tB4C+GWSSZBfxNAlUu8ZJNZDj0yEYDyQkK2e/Pwk1MOwiPr9dVKfR96jGfcaZ2JHt0 IGPXgT2qQyfIHt0WfU9sBCPigHPeE3D0yPNeenffoj4/Bpw0pJUs8m+VqCrvoNwv7nUY/hyltJb vO0tGyk+oD92qC4cPy+ X-Received: by 2002:a05:7300:818c:b0:2c7:3a7:c7b1 with SMTP id 5a478bee46e88-2cbf9503916mr7679632eec.1.1775517923360; Mon, 06 Apr 2026 16:25:23 -0700 (PDT) Received: from dianders.sjc.corp.google.com ([2a00:79e0:2e7c:8:c071:3b78:5a5:824a]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2ca760b0518sm14730975eec.0.2026.04.06.16.25.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Apr 2026 16:25:22 -0700 (PDT) From: Douglas Anderson To: Greg Kroah-Hartman , "Rafael J . Wysocki" , Danilo Krummrich , Alan Stern Cc: Alexey Kardashevskiy , Johan Hovold , Eric Dumazet , Leon Romanovsky , Christoph Hellwig , Robin Murphy , maz@kernel.org, Alexander Lobakin , Saravana Kannan , Douglas Anderson , Andrew Morton , Frank.Li@kernel.org, Jason Gunthorpe , alex@ghiti.fr, alexander.stein@ew.tq-group.com, andre.przywara@arm.com, andrew@codeconstruct.com.au, andrew@lunn.ch, andriy.shevchenko@linux.intel.com, aou@eecs.berkeley.edu, ardb@kernel.org, astewart@tektelic.com, bhelgaas@google.com, brgl@kernel.org, broonie@kernel.org, catalin.marinas@arm.com, chleroy@kernel.org, davem@davemloft.net, david@kernel.org, devicetree@vger.kernel.org, dmaengine@vger.kernel.org, driver-core@lists.linux.dev, gbatra@linux.ibm.com, gregory.clement@bootlin.com, hkallweit1@gmail.com, iommu@lists.linux.dev, jirislaby@kernel.org, joel@jms.id.au, joro@8bytes.org, kees@kernel.org, kevin.brodsky@arm.com, kuba@kernel.org, lenb@kernel.org, lgirdwood@gmail.com, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, linux-riscv@lists.infradead.org, linux-serial@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-usb@vger.kernel.org, linux@armlinux.org.uk, linuxppc-dev@lists.ozlabs.org, m.szyprowski@samsung.com, maddy@linux.ibm.com, mani@kernel.org, miko.lenczewski@arm.com, mpe@ellerman.id.au, netdev@vger.kernel.org, npiggin@gmail.com, osalvador@suse.de, oupton@kernel.org, pabeni@redhat.com, palmer@dabbelt.com, peter.ujfalusi@gmail.com, peterz@infradead.org, pjw@kernel.org, robh@kernel.org, sebastian.hesselbarth@gmail.com, tglx@kernel.org, tsbogend@alpha.franken.de, vgupta@kernel.org, vkoul@kernel.org, will@kernel.org, willy@infradead.org, yangyicong@hisilicon.com, yeoreum.yun@arm.com Subject: [PATCH v5 0/9] driver core: Fix some race conditions Date: Mon, 6 Apr 2026 16:22:53 -0700 Message-ID: <20260406232444.3117516-1-dianders@chromium.org> X-Mailer: git-send-email 2.53.0.1213.gd9a14994de-goog X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The main goal of this series is to fix the observed bug talked about in the first patch ("driver core: Don't let a device probe until it's ready"). That patch fixes a problem that has been observed in the real world and could land even if the rest of the patches are found unacceptable or need to be spun. That said, during patch review Danilo correctly pointed out that many of the bitfield accesses in "struct device" are unsafe. I added a bunch of patches in the series to address each one. Danilo said he's most worried about "can_match", so I put that one first. After that, I tried to transition bitfields to flags in reverse order to when the bitfield was added. Even if transitioning from bitfields to flags isn't truly needed for correctness, it seems silly (and wasteful of space in struct device) to have some in bitfields and some as flags. Thus I didn't spend time for each bitfield showing that it's truly needed for correctness. Transition was done semi manually. Presumably someone skilled at coccinelle could do a better job, but I just used sed in a heavy- handed manner and then reviewed/fixed the results, undoing anything my script got wrong. My terrible/ugly script was: var=can_match caps="${var^^}" for f in $(git grep -l "[>\.]${var}[^1-9_a-zA-Z\[]"); do echo $f sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = true/set_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f" sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = true/dev_set_${caps}(\&\\1)/" "$f" sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = false/clear_bit(DEV_FLAG_${caps}, \&\\1->flags)/" "$f" sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = false/dev_clear_${caps}(\&\\1)/" "$f" sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var} = \([^;]*\)/assign_bit(DEV_FLAG_${caps}, \&\\1->flags, \\2)/" "$f" sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var} = \([^;]*\)/dev_assign_${caps}(\&\\1, \\2)/" "$f" sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)->${var}\([^1-9_a-zA-Z\[]\)/test_bit(DEV_FLAG_${caps}, \&\\1->flags)\\2/" "$f" sed -i~ -e "s/\([a-zA-Z_0-9\.>()-][a-zA-Z_0-9\.>()-]*\)\.${var}\([^1-9_a-zA-Z\[]\)/dev_${caps}(\&\\1)\\2/" "$f" done >From v3 to v4, I transitioned to accessor functions with another ugly sed script. I had git format the old patches, then transformed them with: for f in *.patch; do echo $f sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_test_and_set_\\L\\1(\\2)/" "$f" sed -i~ -e "s/test_and_set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_test_and_set_\\L\\1(\\2)/" "$f" sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_\\L\\1(\\2)/" "$f" sed -i~ -e "s/test_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_\\L\\1(\\2)/" "$f" sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_set_\\L\\1(\\2)/" "$f" sed -i~ -e "s/set_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_set_\\L\\1(\\2)/" "$f" sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags)/dev_clear_\\L\\1(\\2)/" "$f" sed -i~ -e "s/clear_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags)/dev_clear_\\L\\1(\\2)/" "$f" sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \&\(.*\)->flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f" sed -i~ -e "s/assign_bit(DEV_FLAG_\([^,]*\), \(.*\)\.flags, \(.*\))/dev_assign_\\L\\1(\\2, \\3)/" "$f" done ...and then did a few manual touchups for spacing. I only marked the first patch as a "Fix" since it is the only one fixing observed problems. Other patches could be considered fixes too if folks want. I tested the first patch in the series backported to kernel 6.6 on the Pixel phone that was experiencing the race. I added extra printouts to make sure that the problem was hitting / addressed. The rest of the patches are tested with allmodconfig with arm32, arm64, ppc, and x86. I boot tested on an arm64 Chromebook running mainline. Changes in v5: - ready_to_prove => ready_to_probe typo - device_lock() while calling dev_set_ready_to_probe() - Add comment before "can_match = true" from Danilo. - undef __create_dev_flag_accessors Changes in v4: - Use accessor functions for flags Changes in v3: - Use a new "flags" bitfield - Add missing \n in probe error message Changes in v2: - Instead of adjusting the ordering, use "ready_to_probe" flag Douglas Anderson (9): driver core: Don't let a device probe until it's ready driver core: Replace dev->can_match with dev_can_match() driver core: Replace dev->dma_iommu with dev_dma_iommu() driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync() driver core: Replace dev->dma_ops_bypass with dev_dma_ops_bypass() driver core: Replace dev->state_synced with dev_state_synced() driver core: Replace dev->dma_coherent with dev_dma_coherent() driver core: Replace dev->of_node_reused with dev_of_node_reused() driver core: Replace dev->offline + ->offline_disabled with accessors arch/arc/mm/dma.c | 4 +- arch/arm/mach-highbank/highbank.c | 2 +- arch/arm/mach-mvebu/coherency.c | 2 +- arch/arm/mm/dma-mapping-nommu.c | 4 +- arch/arm/mm/dma-mapping.c | 28 ++-- arch/arm64/kernel/cpufeature.c | 2 +- arch/arm64/mm/dma-mapping.c | 2 +- arch/mips/mm/dma-noncoherent.c | 2 +- arch/powerpc/kernel/dma-iommu.c | 8 +- .../platforms/pseries/hotplug-memory.c | 4 +- arch/riscv/mm/dma-noncoherent.c | 2 +- drivers/acpi/scan.c | 2 +- drivers/base/core.c | 55 +++++--- drivers/base/cpu.c | 4 +- drivers/base/dd.c | 36 ++++-- drivers/base/memory.c | 2 +- drivers/base/pinctrl.c | 2 +- drivers/base/platform.c | 2 +- drivers/dma/ti/k3-udma-glue.c | 6 +- drivers/dma/ti/k3-udma.c | 6 +- drivers/iommu/dma-iommu.c | 9 +- drivers/iommu/iommu.c | 5 +- drivers/net/pcs/pcs-xpcs-plat.c | 2 +- drivers/of/device.c | 6 +- drivers/pci/of.c | 2 +- drivers/pci/pwrctrl/core.c | 2 +- drivers/regulator/bq257xx-regulator.c | 2 +- drivers/regulator/rk808-regulator.c | 2 +- drivers/tty/serial/serial_base_bus.c | 2 +- drivers/usb/gadget/udc/aspeed-vhub/dev.c | 2 +- include/linux/device.h | 122 ++++++++++++------ include/linux/dma-map-ops.h | 6 +- include/linux/dma-mapping.h | 2 +- include/linux/iommu-dma.h | 3 +- kernel/cpu.c | 4 +- kernel/dma/mapping.c | 12 +- mm/hmm.c | 2 +- 37 files changed, 218 insertions(+), 142 deletions(-) -- 2.53.0.1213.gd9a14994de-goog