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=1794591455; b=YTvejqYrMTyU03Nm+NuavvSZhpgQgfHQ5dpDIPRfCxPdo0vYKE6bELXSBY5GhX+53nBk oYii1mDIxfzr+DG+NuYJD/edyOUD6LG5jYc8QjeM+N1d0GMk3a+Raz/UbMgmUK4LbMvG/ w9PjsVNpc8K9wWXOwbyp1j6y1Rkl1Cwj/I6UtjHGC0XZrXPufNDDErbjuV02q2m5u7SBu Vhd/N6R9pzlvRpViMgAciVk7N/W4kmdupmHaJig9eI5Yxxiq604dXVJ/B744QnQlzjeKq szv4e/9ptw1GnQOLzhHdJnrywR89C5+f1u7OFroW4EjXO67KguD6pF05kpAlWIzMxIA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591455; 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=3+4yaJGMgg6j43BPPguQU/zXGCAMGBsBT66eyO0P2NM=; b=wOGk/BGx4izmQsc93xUo+1Zq9c6PPO1+/9M4UdDYexbEFQ8pOrv/UvuSAFN9yshjUASp S/xqXNAbsYpHheirDccHlboo8hBmMWyQViuDgdWAe0CfyUe3R5oVcDRKby0Tykf24pC/Q 5Siz8/E1Xd9MEEnJBxF7C8RIG1Zf93UMeTPc2LodgPE8BvaIey6gm7hx2fAejF16dKKG3 uQtpAATlQgst7cxBfNwrC4iRf9IpdsjM1pucXtEErC+Qd869NcM7Uf35w1f9LxY21w3vs cNkXr8rxgk91bADHPqVeH4ZLLMtxm0Pr0vxtBbBW3XJbE0I846P5+v6zbGQgo2booBg== 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=1sw9yK14; 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 05F3E607C352; Fri, 13 Nov 2026 17:37:35 +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=1sw9yK14 Received: by smtp.kernel.org (Postfix) with ESMTPSA id A57E61F000C4; Fri, 13 Nov 2026 17:37:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794591454; bh=3+4yaJGMgg6j43BPPguQU/zXGCAMGBsBT66eyO0P2NM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=1sw9yK14Ta9Pm/Vv3YZ8G8X/+9N+epNh3b/hmbiAzH8m6o8WH4oAEAg3sRjTZyQ9V ANcfgYN5nXd3F8lkXQ2Mr1cwL0CnAmwUnLVErwRiJk417l3luPvXGTuGiF7lT3WOm3 JiNeGKhMERuzoCGPvykSBwPDXEsehNqWDEQnQDYE= 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 6.12 542/670] fbdev: core: Initialize modelist in framebuffer_alloc() Date: Fri, 13 Nov 2026 10:51:46 -0500 Message-ID: <20261113153830.263354594@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153811.177190860@linuxfoundation.org> References: <20261113153811.177190860@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 6.12-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 [ sashal: Adjusted context to place the addition after fbcon_rotate_hint because info->blank initialization is absent. ] 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 4847ebe50d7d7..9b36361bda6e2 100644 --- a/drivers/video/fbdev/core/fb_info.c +++ b/drivers/video/fbdev/core/fb_info.c @@ -42,6 +42,7 @@ struct fb_info *framebuffer_alloc(size_t size, struct device *dev) info->device = dev; info->fbcon_rotate_hint = -1; + INIT_LIST_HEAD(&info->modelist); #if IS_ENABLED(CONFIG_FB_BACKLIGHT) mutex_init(&info->bl_curve_mutex); -- 2.53.0