From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794590145; b=m2ZbOfMQU14rq5QiIYeoGFvBc8tlbalhO5uzZS+NR1RbEhzl49o4snOgTiIJVKxZ9wV9 CqxbZOfytsDi4ytPQ2vXUuN6uEiHBog50cs6z1JfwqSiAJO39OxvouSskcJ3BEeEF+al3 JcDkVSLKFGfzdIFVT2em905LhWJlnilMfq/LohXiK2w5uNXuNlGUWpsRvS7r/++nRnXD7 V+H6F9diWvH0ZW38tT0ohh7r3IHODuXj//5bItQhrdXcblrbZk8t/pZsEto66uxyDI9Df uP0zDRe/Lu6EuARTP4GXQ9vMtcq2+zXuUpAB2L9EIKQtuVSIyW4nkBfg2ofwms4M4kQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590145; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=r7jfxlOOfW99E85TKBtgI0w2BofSiHh2bwzIHHx5TW0=; b=BgE4fOvWp5RvoeU8JyOXGHaYi8bCvZ/K5QY+XBZTMlb+Cm4t6CmKYuaf87CP7OLIXYRZ 1iRAVXqOT4xslvTypkuIiVywcMyPeA+kdpvvMUv+Ozs6Sp6SEmiZcj1trYwwqKdpj+zEw EOkDqwy6Zde6r4pgoVrbwIg8luc0/yw+L7kj27gE3CUpn2fy85f8vG4JjOt9+nH4LB9j1 SPMVcftnXCs4xnILIW+3JaeyvwuNvad2CymOxiG48wwJfBUcyOJt/Zhp394nmQ8xZr3sF NrUkuja2ejvAa4tY3bgyW+eMGBJNPSugMZeS6lAj6DLc+rsWG4lvnj1bOAx714kWqLg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=XU9+ywL6; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 83318606D482; Fri, 13 Nov 2026 17:15:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=XU9+ywL6 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 303B11F000C4; Fri, 13 Nov 2026 17:15:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590145; bh=r7jfxlOOfW99E85TKBtgI0w2BofSiHh2bwzIHHx5TW0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=XU9+ywL6eWoTjDpRZye9rJJWBwidb+F37ag3UmiywB0qz4tOF4dCvpgrEZZ0Fa1e/ 2eyyNk2/YtAYBJyvn8a6ymcjlOMKlrohOC5SfrHYksPB9y9cf5arG8NZFClI+Dw7eq KoZNuzOY6brU8hoKvR5zlL9zN0MxzAmS4suXIw8c= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andrey Misiurov , Helge Deller , Sasha Levin Subject: [PATCH 6.18 161/686] fbdev: core: Initialize modelist in framebuffer_alloc() Date: Fri, 13 Nov 2026 10:44:54 -0500 Message-ID: <20261113153826.239907281@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andrey Misiurov [ Upstream commit 0c9cb9321cb3863b52bdea4b8ae5a27705762c9e ] framebuffer_alloc() returns zeroed memory, so info->modelist starts out with NULL next and prev pointers. The list head is initialized only later, by fb_videomode_to_modelist() or by do_register_framebuffer(). The "fix potential memory leak" commits listed below added fb_destroy_modelist(&info->modelist) to the probe error paths of s3fb, tdfxfb, tridentfb, i740fb and carminefb. These paths can run before the list head is initialized: - s3fb, tdfxfb, tridentfb and i740fb call fb_videomode_to_modelist() only after a successful EDID read, and tridentfb can also hit the error path on an ioremap() or kmalloc() failure before that; - carminefb jumps to the error path when fb_find_mode() fails, before its fb_videomode_to_modelist() call. fb_destroy_modelist() then dereferences the NULL head. Reproduced on Debian 12 (6.1.180) by binding s3fb to a VGA device without EDID and forcing fb_alloc_cmap() to fail: s3fb 0000:00:03.0: cannot allocate colormap BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:fb_destroy_modelist+0x10/0x80 Call Trace: s3_pci_probe.cold+0x12b/0x2bf [s3fb] local_pci_probe+0x41/0x80 pci_device_probe+0xc3/0x240 really_probe+0xde/0x380 __driver_probe_device+0x84/0x150 driver_probe_device+0x1f/0x90 __driver_attach+0xce/0x1c0 bus_for_each_dev+0x87/0xd0 bus_add_driver+0x1ae/0x200 driver_register+0x89/0xe0 do_one_initcall+0x59/0x220 do_init_module+0x4a/0x1f0 Initialize the list head in framebuffer_alloc(), so info->modelist is always a valid, possibly empty, list and fb_destroy_modelist() is safe on every error path. Keep the lazy initialization in do_register_framebuffer(), as drivers that embed struct fb_info rather than calling framebuffer_alloc() still depend on it. Fixes: 3b0ed04bc852 ("fbdev: s3fb: fix potential memory leak in s3_pci_probe()") Fixes: bb019d755366 ("fbdev: tdfxfb: fix potential memory leak in tdfxfb_probe()") Fixes: 7a35ec619d9a ("fbdev: tridentfb: fix potential memory leak in trident_pci_probe()") Fixes: 5936063409af ("fbdev: i740fb: fix potential memory leak in i740fb_probe()") Fixes: 6fcca16a2b19 ("fbdev: carminefb: fix potential memory leak in alloc_carmine_fb()") Cc: stable@vger.kernel.org Signed-off-by: Andrey Misiurov Signed-off-by: Helge Deller Signed-off-by: Sasha Levin --- drivers/video/fbdev/core/fb_info.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/video/fbdev/core/fb_info.c b/drivers/video/fbdev/core/fb_info.c index 52f9bd2c5417a..05988a936bebb 100644 --- a/drivers/video/fbdev/core/fb_info.c +++ b/drivers/video/fbdev/core/fb_info.c @@ -43,6 +43,7 @@ struct fb_info *framebuffer_alloc(size_t size, struct device *dev) info->device = dev; info->fbcon_rotate_hint = -1; info->blank = FB_BLANK_UNBLANK; + INIT_LIST_HEAD(&info->modelist); #if IS_ENABLED(CONFIG_FB_BACKLIGHT) mutex_init(&info->bl_curve_mutex); -- 2.53.0