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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 501C2E88D6D for ; Sat, 4 Apr 2026 00:07:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=9SLtRCjSMs+CJIy1XHFTva2JdvolcAo7xPxCy1V8obU=; b=QSLmCHtPqkntY1 kHESaLWPeYXhamNnDdHm0/eKmSJMhB5enqgPJ6LD0GgKz+NlXYErLy+G1LOp3dT8EHbYnpMgggI0o aTLZuuzE/dr9QlYFfdF5hKWF8m+/BnifG/jX8sOVIAA25vjKOYyu6cNvtXIEO0C4H5WLb31mBQaWm gH72cMrOOS8hITJ83a7spQmZxkH/SLRGdZZ4D8S/OCOZioTEN/eVEOM4DFp7vv3R3w63M+RccnLCG WbWTU1/53UlER9pbXHONZadRzM76FlqeTv8AsNwd7JK6AkMToOA1KH5bFJ9mhJfQTB3aoVNK6H+Ui bIn3lgr4rEzr6s+PdO3g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w8oXs-00000002kch-3OTw; Sat, 04 Apr 2026 00:07:24 +0000 Received: from mail-dy1-x132a.google.com ([2607:f8b0:4864:20::132a]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w8oXp-00000002kbd-2EOd for linux-riscv@lists.infradead.org; Sat, 04 Apr 2026 00:07:23 +0000 Received: by mail-dy1-x132a.google.com with SMTP id 5a478bee46e88-2cc4c693d59so2340908eec.1 for ; Fri, 03 Apr 2026 17:07:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1775261240; x=1775866040; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=KGKsMy9vhlN9yvdnOvYy+R4lmavPYuTzTATeThGwgQc=; b=nAzCLfc/SZYVYgd0knvrPUnyS1QtgItVdxVjqjtvjURxhqsJtBO1jSBpuhctShud2u 4Rz9PX5l7gixtY30n/+EpD0Isn8XrBaE4NVqcJvpKgvM0iCWgfKUFUeiRrDyJzqbH5YV oHFNDJLhcVU6NtcxM50CLJGPx2PNjVg5zyzg8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775261240; x=1775866040; 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=KGKsMy9vhlN9yvdnOvYy+R4lmavPYuTzTATeThGwgQc=; b=c0v1J7HXiEZwV30Q8AQn2tFQsrd1HEbkPl91ywpvGEPr09H2FXwcDSUJ/469GCu1rp PlNIQVVtTzIN4jQS7wRKlXfyLjoC8DoxThddMjdZG4dbB8z3gTrAOthJ7hXgFuopY5NH pfyxqKOE8/kuFBEJ/MpeuMiN7sMYLf+LsIHdGo33aZ/+ukLIF10iFeSFFm3tH+jHND7a +J0TOpwDRI7FjEz8fWwkzIFy0bziq7mOODi+dU9rqQGeEAUvxIFDRNNGSRSLdwiJnnV8 JjUgJGmcuD0xPixh/bSuzuIYQXTF93k4+QOp8bj0dvvA/76uUm3x8eEdpxInWLedHmmJ JAeQ== X-Forwarded-Encrypted: i=1; AJvYcCWiniGNOleFfR6tskjzZ5BCItt3VrEY2qVdPlHtxdbkcQ8gPea5L9H3UADEAIxFfi+RT6MHAlkVHXMpQw==@lists.infradead.org X-Gm-Message-State: AOJu0YzW5WV7L5eegx2I8gkH7OqIvGBtbuYipvBT3cc3BU00NA73WQLo rM2Lapo7J5w5buHm+9deWsT1RAchQ3m+HeXLd6s2fYGUMDyW4xB0AUV6miOcvFBhQA== X-Gm-Gg: AeBDieuECnqZ1RmoxwRviEpnts6RNkM72lcvNuoAEXQ9OM2HkqmITOXnVeR97Djjt9Y Xc2bu5VZWDZSfOWHFw5j2sg1ur+Zb0b38vktgE8O21lnS9IhZUtjWumzIY1nuLLXwUXDcu6DH4h m5e3iLhW+rv4s1rzpr54iiUr81RIvISc6Wo4yzhU5/0HrKlWMjWnI5bCDMlLsTXspC6gs/8SloL yb4b8zvL75p+yRwkBLt3ZOwjnA84YBtrxHr3TPyHKT6VgoYB7HQpBasbIaQmkk5s1M2QtzReW8n qE/W5Uk+RQ2p8JIPrcTqgOWPYulwJA+TpAsjzOVTUW45Dwn98G5umEYjWO5RGZwM/32kU8glVf6 ByWfqLrK8qqS0UvJ8P6lhCcF4xKm4luchp57AtyIjgSCd6NNGQx1SneekGqW7y499CP/4m8UTBr MrFzQLc843zDuvXD9g2C7wlqLsibMq56+tJR6OMCXLdaK5gP5TWPukP/zT2BhBwjpdcoD648otr noRrPM/XME= X-Received: by 2002:a05:7300:5722:b0:2c7:ea98:da0 with SMTP id 5a478bee46e88-2cbfbc8aeb9mr2680118eec.19.1775261240285; Fri, 03 Apr 2026 17:07:20 -0700 (PDT) Received: from dianders.sjc.corp.google.com ([2a00:79e0:2e7c:8:a8b6:55b2:3eb6:2c0e]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2ca79e1d93bsm6520716eec.12.2026.04.03.17.07.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Apr 2026 17:07:19 -0700 (PDT) From: Douglas Anderson To: Greg Kroah-Hartman , "Rafael J . Wysocki" , Danilo Krummrich , Alan Stern Cc: Saravana Kannan , Christoph Hellwig , Eric Dumazet , Johan Hovold , Leon Romanovsky , Alexander Lobakin , Alexey Kardashevskiy , Robin Murphy , 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, 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, maz@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 v4 0/9] driver core: Fix some race conditions Date: Fri, 3 Apr 2026 17:04:54 -0700 Message-ID: <20260404000644.522677-1-dianders@chromium.org> X-Mailer: git-send-email 2.53.0.1213.gd9a14994de-goog MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260403_170721_723890_671CB978 X-CRM114-Status: GOOD ( 23.69 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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. NOTE: one potentially "controversial" choice I made in some patches was to always reserve a flag ID even if a flag is only used under certain CONFIG_ settings. This is a change from how things were before. Keeping the numbering consistent and allowing easy compile-testing of both CONFIG settings seemed worth it, especially since it won't take up any extra space until we've added a lot more flags. 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 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 | 53 +++++--- drivers/base/cpu.c | 4 +- drivers/base/dd.c | 28 ++-- 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 | 120 ++++++++++++------ 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, 206 insertions(+), 142 deletions(-) -- 2.53.0.1213.gd9a14994de-goog _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv