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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 36DACD12D69 for ; Wed, 3 Dec 2025 14:09:16 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B30AD10E7ED; Wed, 3 Dec 2025 14:09:15 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="FClpNQ9H"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 82DC810E7BD; Wed, 3 Dec 2025 13:19:14 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 3CE45438ED; Wed, 3 Dec 2025 13:19:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5461AC4CEFB; Wed, 3 Dec 2025 13:19:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1764767954; bh=S6gmzWnwTh6tOEneCcIVJqxgW0S11eCqJRiu7VZJt/w=; h=Subject:To:Cc:From:Date:In-Reply-To:From; b=FClpNQ9HTSREROUsvbX2+gBdwPChgw3Jl6w70/oJCfPuwPmZhDpN6kYSw+KKSANtj ZqWsdM68xpho2sZ4whc2kHXBD9q4bRvhcBDg/nb3vKY8ZZYwJsHpEivzuOjDVj9xPK e4y0z+iVYp9le5QIR+31S5uJlq9gWiZOUJs9d4Pk= Subject: Patch "drm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup" has been added to the 6.12-stable tree To: alexander.deucher@amd.com, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, gregkh@linuxfoundation.org, javierm@redhat.com, nouveau@lists.freedesktop.org, sashal@kernel.org, tzimmermann@suse.de Cc: From: Date: Wed, 03 Dec 2025 14:19:11 +0100 In-Reply-To: <20251202202312.2505097-1-sashal@kernel.org> Message-ID: <2025120310-trump-rancidity-eedb@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit X-stable: commit X-Patchwork-Hint: ignore X-Mailman-Approved-At: Wed, 03 Dec 2025 14:09:14 +0000 X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" This is a note to let you know that I've just added the patch titled drm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup to the 6.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-fbcon-vga_switcheroo-avoid-race-condition-in-fbcon-setup.patch and it can be found in the queue-6.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From stable+bounces-198144-greg=kroah.com@vger.kernel.org Tue Dec 2 21:23:22 2025 From: Sasha Levin Date: Tue, 2 Dec 2025 15:23:12 -0500 Subject: drm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup To: stable@vger.kernel.org Cc: Thomas Zimmermann , Javier Martinez Canillas , Alex Deucher , dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, linux-fbdev@vger.kernel.org, Sasha Levin Message-ID: <20251202202312.2505097-1-sashal@kernel.org> From: Thomas Zimmermann [ Upstream commit eb76d0f5553575599561010f24c277cc5b31d003 ] Protect vga_switcheroo_client_fb_set() with console lock. Avoids OOB access in fbcon_remap_all(). Without holding the console lock the call races with switching outputs. VGA switcheroo calls fbcon_remap_all() when switching clients. The fbcon function uses struct fb_info.node, which is set by register_framebuffer(). As the fb-helper code currently sets up VGA switcheroo before registering the framebuffer, the value of node is -1 and therefore not a legal value. For example, fbcon uses the value within set_con2fb_map() [1] as an index into an array. Moving vga_switcheroo_client_fb_set() after register_framebuffer() can result in VGA switching that does not switch fbcon correctly. Therefore move vga_switcheroo_client_fb_set() under fbcon_fb_registered(), which already holds the console lock. Fbdev calls fbcon_fb_registered() from within register_framebuffer(). Serializes the helper with VGA switcheroo's call to fbcon_remap_all(). Although vga_switcheroo_client_fb_set() takes an instance of struct fb_info as parameter, it really only needs the contained fbcon state. Moving the call to fbcon initialization is therefore cleaner than before. Only amdgpu, i915, nouveau and radeon support vga_switcheroo. For all other drivers, this change does nothing. Signed-off-by: Thomas Zimmermann Link: https://elixir.bootlin.com/linux/v6.17/source/drivers/video/fbdev/core/fbcon.c#L2942 # [1] Fixes: 6a9ee8af344e ("vga_switcheroo: initial implementation (v15)") Acked-by: Javier Martinez Canillas Acked-by: Alex Deucher Cc: dri-devel@lists.freedesktop.org Cc: nouveau@lists.freedesktop.org Cc: amd-gfx@lists.freedesktop.org Cc: linux-fbdev@vger.kernel.org Cc: # v2.6.34+ Link: https://patch.msgid.link/20251105161549.98836-1-tzimmermann@suse.de Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_fb_helper.c | 6 ------ drivers/gpu/drm/i915/display/intel_fbdev.c | 6 ------ drivers/gpu/drm/radeon/radeon_fbdev.c | 5 ----- drivers/video/fbdev/core/fbcon.c | 9 +++++++++ 4 files changed, 9 insertions(+), 17 deletions(-) --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -30,9 +30,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include -#include #include -#include #include #include @@ -1637,10 +1635,6 @@ static int drm_fb_helper_single_fb_probe strcpy(fb_helper->fb->comm, "[fbcon]"); - /* Set the fb info for vgaswitcheroo clients. Does nothing otherwise. */ - if (dev_is_pci(dev->dev)) - vga_switcheroo_client_fb_set(to_pci_dev(dev->dev), fb_helper->info); - return 0; } --- a/drivers/gpu/drm/i915/display/intel_fbdev.c +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c @@ -589,11 +589,8 @@ static int intel_fbdev_restore_mode(stru static void intel_fbdev_client_unregister(struct drm_client_dev *client) { struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); - struct drm_device *dev = fb_helper->dev; - struct pci_dev *pdev = to_pci_dev(dev->dev); if (fb_helper->info) { - vga_switcheroo_client_fb_set(pdev, NULL); drm_fb_helper_unregister_info(fb_helper); } else { drm_fb_helper_unprepare(fb_helper); @@ -620,7 +617,6 @@ static int intel_fbdev_client_hotplug(st { struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); struct drm_device *dev = client->dev; - struct pci_dev *pdev = to_pci_dev(dev->dev); int ret; if (dev->fb_helper) @@ -634,8 +630,6 @@ static int intel_fbdev_client_hotplug(st if (ret) goto err_drm_fb_helper_fini; - vga_switcheroo_client_fb_set(pdev, fb_helper->info); - return 0; err_drm_fb_helper_fini: --- a/drivers/gpu/drm/radeon/radeon_fbdev.c +++ b/drivers/gpu/drm/radeon/radeon_fbdev.c @@ -300,10 +300,8 @@ static void radeon_fbdev_client_unregist { struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); struct drm_device *dev = fb_helper->dev; - struct radeon_device *rdev = dev->dev_private; if (fb_helper->info) { - vga_switcheroo_client_fb_set(rdev->pdev, NULL); drm_helper_force_disable_all(dev); drm_fb_helper_unregister_info(fb_helper); } else { @@ -325,7 +323,6 @@ static int radeon_fbdev_client_hotplug(s { struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client); struct drm_device *dev = client->dev; - struct radeon_device *rdev = dev->dev_private; int ret; if (dev->fb_helper) @@ -342,8 +339,6 @@ static int radeon_fbdev_client_hotplug(s if (ret) goto err_drm_fb_helper_fini; - vga_switcheroo_client_fb_set(rdev->pdev, fb_helper->info); - return 0; err_drm_fb_helper_fini: --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -65,6 +65,7 @@ #include #include #include +#include #include #include #include @@ -77,6 +78,7 @@ #include #include /* For counting font checksums */ #include +#include #include #include "fbcon.h" @@ -2894,6 +2896,9 @@ void fbcon_fb_unregistered(struct fb_inf console_lock(); + if (info->device && dev_is_pci(info->device)) + vga_switcheroo_client_fb_set(to_pci_dev(info->device), NULL); + fbcon_registered_fb[info->node] = NULL; fbcon_num_registered_fb--; @@ -3027,6 +3032,10 @@ static int do_fb_registered(struct fb_in } } + /* Set the fb info for vga_switcheroo clients. Does nothing otherwise. */ + if (info->device && dev_is_pci(info->device)) + vga_switcheroo_client_fb_set(to_pci_dev(info->device), info); + return ret; } Patches currently in stable-queue which might be from sashal@kernel.org are queue-6.12/usb-typec-ucsi-psy-set-max-current-to-zero-when-disconnected.patch queue-6.12/net-fec-do-not-update-perout-if-it-is-enabled.patch queue-6.12/spi-nxp-fspi-propagate-fwnode-in-acpi-case-as-well.patch queue-6.12/spi-amlogic-spifc-a1-handle-devm_pm_runtime_enable-e.patch queue-6.12/can-gs_usb-gs_usb_receive_bulk_callback-check-actual.patch queue-6.12/drm-xe-fix-conversion-from-clock-ticks-to-millisecon.patch queue-6.12/mm-huge_memory-fix-null-pointer-deference-when-splitting-folio.patch queue-6.12/usb-gadget-udc-fix-use-after-free-in-usb_gadget_state_work.patch queue-6.12/spi-spi-nxp-fspi-remove-the-goto-in-probe.patch queue-6.12/net-atlantic-fix-fragment-overflow-handling-in-rx-pa.patch queue-6.12/bluetooth-btusb-mediatek-fix-kernel-crash-when-relea.patch queue-6.12/mailbox-mtk-cmdq-refine-dma-address-handling-for-the.patch queue-6.12/bluetooth-hci_core-fix-triggering-cmd_timer-for-hci_.patch queue-6.12/platform-x86-intel-punit_ipc-fix-memory-corruption.patch queue-6.12/veth-reduce-xdp-no_direct-return-section-to-fix-race.patch queue-6.12/net-sched-generalize-check-for-no-queue-qdisc-on-tx-.patch queue-6.12/iio-st_lsm6dsx-fixed-calibrated-timestamp-calculatio.patch queue-6.12/net-lan966x-fix-the-initialization-of-taprio.patch queue-6.12/net-phy-mxl-gpy-fix-bogus-error-on-usxgmii-and-integ.patch queue-6.12/can-rcar_canfd-fix-can-fd-mode-as-default.patch queue-6.12/net-dsa-sja1105-simplify-static-configuration-reload.patch queue-6.12/veth-apply-qdisc-backpressure-on-full-ptr_ring-to-re.patch queue-6.12/bluetooth-hci_sock-prevent-race-in-socket-write-iter.patch queue-6.12/net-fec-do-not-allow-enabling-pps-and-perout-simulta.patch queue-6.12/net-sxgbe-fix-potential-null-dereference-in-sxgbe_rx.patch queue-6.12/net-dsa-microchip-do-not-execute-ptp-driver-code-for-unsupported-switches.patch queue-6.12/spi-spi-mem-add-a-new-controller-capability.patch queue-6.12/net-dsa-sja1105-fix-sgmii-linking-at-10m-or-100m-but.patch queue-6.12/fs-namespace-fix-reference-leak-in-grab_requested_mn.patch queue-6.12/usb-gadget-renesas_usbf-handle-devm_pm_runtime_enabl.patch queue-6.12/veth-prevent-null-pointer-dereference-in-veth_xdp_rc.patch queue-6.12/drm-amdgpu-fix-cyan_skillfish2-gpu-info-fw-handling.patch queue-6.12/mailbox-pcc-refactor-error-handling-in-irq-handler-i.patch queue-6.12/net-fec-cancel-perout_timer-when-perout-is-disabled.patch queue-6.12/net-mlx5e-fix-validation-logic-in-rate-limiting.patch queue-6.12/eth-fbnic-fix-counter-roll-over-issue.patch queue-6.12/net-fec-do-not-register-pps-event-for-perout.patch queue-6.12/spi-spi-mem-allow-specifying-the-byte-order-in-octal.patch queue-6.12/net-wwan-mhi-keep-modem-name-match-with-foxconn-t99w.patch queue-6.12/can-kvaser_usb-leaf-fix-potential-infinite-loop-in-c.patch queue-6.12/mailbox-mailbox-test-fix-debugfs_create_dir-error-ch.patch queue-6.12/veth-more-robust-handing-of-race-to-avoid-txq-gettin.patch queue-6.12/usb-udc-add-trace-event-for-usb_gadget_set_state.patch queue-6.12/spi-spi-mem-extend-spi-mem-operations-with-a-per-ope.patch queue-6.12/net-dsa-microchip-free-previously-initialized-ports-on-init-failures.patch queue-6.12/drm-fbcon-vga_switcheroo-avoid-race-condition-in-fbcon-setup.patch queue-6.12/spi-bcm63xx-fix-premature-cs-deassertion-on-rx-only-.patch queue-6.12/spi-nxp-fspi-support-per-spi-mem-operation-frequency.patch queue-6.12/spi-spi-nxp-fspi-add-oct-dtr-mode-support.patch queue-6.12/net-dsa-microchip-fix-symetry-in-ksz_ptp_msg_irq_-setup-free.patch queue-6.12/spi-tegra114-remove-kconfig-dependency-on-tegra20_ap.patch queue-6.12/can-gs_usb-gs_usb_xmit_callback-fix-handling-of-fail.patch queue-6.12/team-move-team-device-type-change-at-the-end-of-team.patch queue-6.12/net-aquantia-add-missing-descriptor-cache-invalidati.patch queue-6.12/bluetooth-smp-fix-not-generating-mackey-and-ltk-when.patch queue-6.12/mailbox-pcc-don-t-zero-error-register.patch queue-6.12/can-gs_usb-gs_usb_receive_bulk_callback-check-actual.patch-29525