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 28CF4E88D73 for ; Sat, 4 Apr 2026 00:07:26 +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=Bjp808tY5tPCgLxI6wrAbUrANxFplb7znnXT8GabNgQ=; b=APBoTyMJo7emaj NlP6JTiuDpnUZk/NvWEofomJhiz8Jg3S3LcJKbwWJR/GvkiOv0XiCw1Y1WzNuXI3H5ovRFRxev96m EMytopXv1S1Eaj09yYvsJbJjaKUNJscxCEdy8UgmK59sKZgz3DUZpIJMcv1Lp/igm7wufbhjX9sia 7LMZTgAzBqN7lJ2/ue/1eramoBYzqi+WfS6QQIzkFZpubDk0OYKdlgV2vfbwj9Ylebkqc4ZuHNkbV Se+G4fUzdt1FtsQGEZ5FXzcT4mHgCeKSrS2uvDwll+ipX3HMtTKOWg60h7+a8Y6LyqB4D67VObxoD F5qKkIPR8jjY5PQqjDuQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w8oXt-00000002kcl-0b79; Sat, 04 Apr 2026 00:07:25 +0000 Received: from mail-dy1-x132e.google.com ([2607:f8b0:4864:20::132e]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w8oXp-00000002kbf-2Qyx for linux-snps-arc@lists.infradead.org; Sat, 04 Apr 2026 00:07:23 +0000 Received: by mail-dy1-x132e.google.com with SMTP id 5a478bee46e88-2c1632faeb9so4450975eec.0 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=h1O7kgvYeTvrdnueVGOj1krgDW0BDysfUfIbKX/jt32UmB/gs1WQXvT1dl7ikFfxfQ g4aNpNYRHfHdgxBW8UuJLUk4EJm4a48y+Di266VzKekFxEXqtbRzMx8/yQW25I2ypzQf il3oPhSfsGhw+n6avW1RZDKkRa1MQBLH4txv7fMPB1KmTs/SkTBEmZ70w5RTe+SVYosv GVxij+YHBzntd2e9hUNi6EvujYSNJDFj8muFl8T65z5pVl3Ez1B7UCMfSrQk2jwgp7R9 JSvft1rYDfu12Uq6cjnssF0JFsspB0nzRiOjLmUsh3QNY4oEyKOqfsNNSLRqvc9XggWz GpfA== X-Forwarded-Encrypted: i=1; AJvYcCVVOJVkeKHMvldrcUMEdYTfWr5+6CWidaIzH2OX4EbLRxFs1IWsKbCCSRKz24Thp18Dethp9w+1T+X3LLLb4Q==@lists.infradead.org X-Gm-Message-State: AOJu0YwRiPa/u2qOLRHZT0CmKGoMyOVf9e38/9p8z+hzqK5YZhap0dB5 PafNCNmocU06XDDAvoa8WsX5+R/uf+Hqdw2ekR8kWB4l+xvgISfY5D77ys0pf6JIBQ== X-Gm-Gg: AeBDiet9Elrn+TLubH8dkiRlp2MOFfAzPiW9mue2CRo5QA3aC9HaLcgckOc5j7ZAG0H Cr06KUcREtDLLq0D1kGIZwmz8ChmJ9KUrSwr34LdKMpMFcs+NZYdS0Mi1URllGPLiV2pvneehdj tDmuelDxO4sK94XtFeQVS47WuOdejPM093p89NgJ+LNxQYG7X70h4Y+2auz/Ktue00WQSFpMPEL IhkocXHQiayBDjb5dqGDjYQPph5TNawvI7zffX8QqzC3t/O4wNP0MnJUwQQ+8tp/1LJUQpN+k0A JV3B2HBoriAV3MRg1z3n5+fVX5p5whYsEcFV+AVdKWR42/8INTWk44LGGD+4HVdLWLJEyuCzKdi pLRHrIvc2l172znDmC6n6IOzkSgA+bKTKADCy4PcYJXOtsPFLu42NBT+2zWiRgLWpo+n0SAlcAv 2b9wslOJyvwEhJTMtg6+OYYBhgPoM1W+A8S7+AI4fwzfs2elbf3hjm/P8ZPlMjf7UsyGQ97929+ p9HBCt2qX4= 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_728893_102F09AF X-CRM114-Status: GOOD ( 23.69 ) X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+linux-snps-arc=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-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc