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=1794064688; b=txaRHJ1F/F9OAbRIXrO4+Mb/IsDWEk5NK46fA98WaJv/0YwNNO6ZoPoTZnAzFnoy0L1Y Nz4wxQgZLolUHXm2PfsMUJUzKU59D3a8v7jEZ2AHxhFPmFpxO200i3C+edp2Wi366n1Hi tnNqMMqSrjQ1/lg6ICu7+9O3fIepWZoW9FN8Zw7EWkwwqewpELizbXWBKHfL0BYNtB/6c uJyD3AAFbb30Oo4ebnhusDXFI1yfiCM02s7eSfkWCGZyGV5xDNRAomyl5DJCPFk70OQLU ATBbEb7tduuJscv2uCKikN/T3ItfZDhFgJcl4xkf+ViLPmBPnQ7uyO5iJOpk8mvXSNA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794064688; 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=Uj5oaxsHIbLj+BHzJcPReUMRGTYIS7amwhQNwxw5Mf8=; b=rbhkQamcbwpeZGfsSJ3YVno/1gL53WeTxuzUNgiBRhtCkFCnBzVf14XpW81kItUaUhsZ G5AqejsnCYB+h1rRX6nDVO5Fl8PZs+7n9JLINmxkQiiaQUPMQKHPl6tdW3CuxEDZ+WHLb eRNPV+qMIQWRRKteciLxgc7F0ajbn8w/SfnRsL00MVpOT0us/OzwHAftqxfqFR0dOxUch ZlOwzz0qAjQc8kSrlB4BWAtjCLtPYBFJISRTyTRe5T2r4d57L4J8YCnrVa1U+yvOgjheR 1ESGuH/3PAFQwXf5Bcz/G4pujErhfw+ClJrbIOyRaJRbs30XHqHIa0Gagpe45AGU1Yg== 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=NSxoqKQb; 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 A2FC4606B8AE; Sat, 7 Nov 2026 15:18:08 +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=NSxoqKQb Received: by smtp.kernel.org (Postfix) with ESMTPSA id 520E41F0089F; Sat, 7 Nov 2026 15:18:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794064688; bh=Uj5oaxsHIbLj+BHzJcPReUMRGTYIS7amwhQNwxw5Mf8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=NSxoqKQbR4EbvTR6Gncrf/n/ZQ4SaXo88hHO3YN4bmylfOCcxKZN24wjtLeiz0zH1 uP+HyRPKnzYNxvdmKe1RmsO/NW3Uqj++pCoaOTvMmk6FRVlLQ78YEi8A50TJBovKUy Xn/emfGCjIp3yWiA7d1oFQ0KygGB7+TVl6HbIw3I= 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 7.3 0682/1257] fbdev: core: Initialize modelist in framebuffer_alloc() Date: Sat, 7 Nov 2026 08:49:38 -0500 Message-ID: <20261107134958.102182102@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@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 7.3-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