From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DE02E308F01; Mon, 13 Oct 2025 15:44:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760370275; cv=none; b=NoCrxhtvh8QGxiEBZo/RdAwxpcS8z5IYqW03BDAOjyRlNu3RRqIk3xthrh58V6sXnOabq/FN1D2GWVv/IUCX8ITMCC5WIkmYFr0Q1aICHHYDUh3P1+wbC7JAeKlQW4f+i8Uk8dy+XvU3j3eqUImLMdqnPRx4T2YYmLZrRBDWasw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760370275; c=relaxed/simple; bh=PIuGIzhnIHbntyeEHT8BlkjIpcSm/aeQ8EYh61h9Kyc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UQLTd+NiQjobXrkb+m4AlykUzmik8tp5sPdOYxzyfLVBzircqrakG70pe5hIDi6lAnKrLe3kEbhZdylEQubqZfOXDAVlzVkQBG27TLTcfmaz/JBKBdTksQ9EWEo2uqaRJsbM1n04C8UGjcEDug+4gx1P3kIJzC48RH4r+f5MiMo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1X36cfrd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1X36cfrd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D010C4CEE7; Mon, 13 Oct 2025 15:44:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760370274; bh=PIuGIzhnIHbntyeEHT8BlkjIpcSm/aeQ8EYh61h9Kyc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1X36cfrdlGZuCqZO0PTdWsyr54BXYIWFcw+w+6hwrpz8V5CR6kWcdZNQO/jUMwIqh QOiy8Sd+rLJZPObyETpyl/O1LQRlFPmb9/aToGwoeJ3IMKgUdHTKhduq62Gf6RvYuW sFOuBbETnGwIhJZEUR6M0HSIpqGxoxKhZCL7ktSc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Daniel Huhardeaux , Janne Grunau , Hans de Goede , Helge Deller Subject: [PATCH 6.17 539/563] fbdev: simplefb: Fix use after free in simplefb_detach_genpds() Date: Mon, 13 Oct 2025 16:46:40 +0200 Message-ID: <20251013144430.834539197@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251013144411.274874080@linuxfoundation.org> References: <20251013144411.274874080@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Janne Grunau commit da1bb9135213744e7ec398826c8f2e843de4fb94 upstream. The pm_domain cleanup can not be devres managed as it uses struct simplefb_par which is allocated within struct fb_info by framebuffer_alloc(). This allocation is explicitly freed by unregister_framebuffer() in simplefb_remove(). Devres managed cleanup runs after the device remove call and thus can no longer access struct simplefb_par. Call simplefb_detach_genpds() explicitly from simplefb_destroy() like the cleanup functions for clocks and regulators. Fixes an use after free on M2 Mac mini during aperture_remove_conflicting_devices() using the downstream asahi kernel with Debian's kernel config. For unknown reasons this started to consistently dereference an invalid pointer in v6.16.3 based kernels. [ 6.736134] BUG: KASAN: slab-use-after-free in simplefb_detach_genpds+0x58/0x220 [ 6.743545] Read of size 4 at addr ffff8000304743f0 by task (udev-worker)/227 [ 6.750697] [ 6.752182] CPU: 6 UID: 0 PID: 227 Comm: (udev-worker) Tainted: G S 6.16.3-asahi+ #16 PREEMPTLAZY [ 6.752186] Tainted: [S]=CPU_OUT_OF_SPEC [ 6.752187] Hardware name: Apple Mac mini (M2, 2023) (DT) [ 6.752189] Call trace: [ 6.752190] show_stack+0x34/0x98 (C) [ 6.752194] dump_stack_lvl+0x60/0x80 [ 6.752197] print_report+0x17c/0x4d8 [ 6.752201] kasan_report+0xb4/0x100 [ 6.752206] __asan_report_load4_noabort+0x20/0x30 [ 6.752209] simplefb_detach_genpds+0x58/0x220 [ 6.752213] devm_action_release+0x50/0x98 [ 6.752216] release_nodes+0xd0/0x2c8 [ 6.752219] devres_release_all+0xfc/0x178 [ 6.752221] device_unbind_cleanup+0x28/0x168 [ 6.752224] device_release_driver_internal+0x34c/0x470 [ 6.752228] device_release_driver+0x20/0x38 [ 6.752231] bus_remove_device+0x1b0/0x380 [ 6.752234] device_del+0x314/0x820 [ 6.752238] platform_device_del+0x3c/0x1e8 [ 6.752242] platform_device_unregister+0x20/0x50 [ 6.752246] aperture_detach_platform_device+0x1c/0x30 [ 6.752250] aperture_detach_devices+0x16c/0x290 [ 6.752253] aperture_remove_conflicting_devices+0x34/0x50 ... [ 6.752343] [ 6.967409] Allocated by task 62: [ 6.970724] kasan_save_stack+0x3c/0x70 [ 6.974560] kasan_save_track+0x20/0x40 [ 6.978397] kasan_save_alloc_info+0x40/0x58 [ 6.982670] __kasan_kmalloc+0xd4/0xd8 [ 6.986420] __kmalloc_noprof+0x194/0x540 [ 6.990432] framebuffer_alloc+0xc8/0x130 [ 6.994444] simplefb_probe+0x258/0x2378 ... [ 7.054356] [ 7.055838] Freed by task 227: [ 7.058891] kasan_save_stack+0x3c/0x70 [ 7.062727] kasan_save_track+0x20/0x40 [ 7.066565] kasan_save_free_info+0x4c/0x80 [ 7.070751] __kasan_slab_free+0x6c/0xa0 [ 7.074675] kfree+0x10c/0x380 [ 7.077727] framebuffer_release+0x5c/0x90 [ 7.081826] simplefb_destroy+0x1b4/0x2c0 [ 7.085837] put_fb_info+0x98/0x100 [ 7.089326] unregister_framebuffer+0x178/0x320 [ 7.093861] simplefb_remove+0x3c/0x60 [ 7.097611] platform_remove+0x60/0x98 [ 7.101361] device_remove+0xb8/0x160 [ 7.105024] device_release_driver_internal+0x2fc/0x470 [ 7.110256] device_release_driver+0x20/0x38 [ 7.114529] bus_remove_device+0x1b0/0x380 [ 7.118628] device_del+0x314/0x820 [ 7.122116] platform_device_del+0x3c/0x1e8 [ 7.126302] platform_device_unregister+0x20/0x50 [ 7.131012] aperture_detach_platform_device+0x1c/0x30 [ 7.136157] aperture_detach_devices+0x16c/0x290 [ 7.140779] aperture_remove_conflicting_devices+0x34/0x50 ... Reported-by: Daniel Huhardeaux Cc: stable@vger.kernel.org Fixes: 92a511a568e44 ("fbdev/simplefb: Add support for generic power-domains") Signed-off-by: Janne Grunau Reviewed-by: Hans de Goede Signed-off-by: Helge Deller Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/simplefb.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) --- a/drivers/video/fbdev/simplefb.c +++ b/drivers/video/fbdev/simplefb.c @@ -93,6 +93,7 @@ struct simplefb_par { static void simplefb_clocks_destroy(struct simplefb_par *par); static void simplefb_regulators_destroy(struct simplefb_par *par); +static void simplefb_detach_genpds(void *res); /* * fb_ops.fb_destroy is called by the last put_fb_info() call at the end @@ -105,6 +106,7 @@ static void simplefb_destroy(struct fb_i simplefb_regulators_destroy(info->par); simplefb_clocks_destroy(info->par); + simplefb_detach_genpds(info->par); if (info->screen_base) iounmap(info->screen_base); @@ -445,13 +447,14 @@ static void simplefb_detach_genpds(void if (!IS_ERR_OR_NULL(par->genpds[i])) dev_pm_domain_detach(par->genpds[i], true); } + par->num_genpds = 0; } static int simplefb_attach_genpds(struct simplefb_par *par, struct platform_device *pdev) { struct device *dev = &pdev->dev; - unsigned int i; + unsigned int i, num_genpds; int err; err = of_count_phandle_with_args(dev->of_node, "power-domains", @@ -465,26 +468,35 @@ static int simplefb_attach_genpds(struct return err; } - par->num_genpds = err; + num_genpds = err; /* * Single power-domain devices are handled by the driver core, so * nothing to do here. */ - if (par->num_genpds <= 1) + if (num_genpds <= 1) { + par->num_genpds = num_genpds; return 0; + } - par->genpds = devm_kcalloc(dev, par->num_genpds, sizeof(*par->genpds), + par->genpds = devm_kcalloc(dev, num_genpds, sizeof(*par->genpds), GFP_KERNEL); if (!par->genpds) return -ENOMEM; - par->genpd_links = devm_kcalloc(dev, par->num_genpds, + par->genpd_links = devm_kcalloc(dev, num_genpds, sizeof(*par->genpd_links), GFP_KERNEL); if (!par->genpd_links) return -ENOMEM; + /* + * Set par->num_genpds only after genpds and genpd_links are allocated + * to exit early from simplefb_detach_genpds() without full + * initialisation. + */ + par->num_genpds = num_genpds; + for (i = 0; i < par->num_genpds; i++) { par->genpds[i] = dev_pm_domain_attach_by_id(dev, i); if (IS_ERR(par->genpds[i])) { @@ -506,9 +518,10 @@ static int simplefb_attach_genpds(struct dev_warn(dev, "failed to link power-domain %u\n", i); } - return devm_add_action_or_reset(dev, simplefb_detach_genpds, par); + return 0; } #else +static void simplefb_detach_genpds(void *res) { } static int simplefb_attach_genpds(struct simplefb_par *par, struct platform_device *pdev) { @@ -622,18 +635,20 @@ static int simplefb_probe(struct platfor ret = devm_aperture_acquire_for_platform_device(pdev, par->base, par->size); if (ret) { dev_err(&pdev->dev, "Unable to acquire aperture: %d\n", ret); - goto error_regulators; + goto error_genpds; } ret = register_framebuffer(info); if (ret < 0) { dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret); - goto error_regulators; + goto error_genpds; } dev_info(&pdev->dev, "fb%d: simplefb registered!\n", info->node); return 0; +error_genpds: + simplefb_detach_genpds(par); error_regulators: simplefb_regulators_destroy(par); error_clocks: