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=1794063315; b=EYXypLvy5u3xvDfuNcMeRs8LztEXPB5qML/O0iIVlblY0wcsX47rFzlMGl+z3EN6DypM UkmY5Ud3DkniAZjtzS3J0YrEZxxIJzYcBgja6y5145LNvUdHAANXN+qQN8DCHnmMe6uVX bQ1SroYQIsgwJplxMVMoTZfnSA4Y5GXZeknhWLmy9WzJ/fiYeb6JDeIv5/OZqWiTgmV97 0ysNkPNAGWetLrsCosTHxWlvQ/+WNoJFD6MQau3/SjoAsjZZsx7/s6mbcZ6LPC5SRBCkP QtbrFjDU77xTPIXu/mi9XqrkFUEizL7tE3Fp/ifZgx+aNW6xx917X7IpsxZX667Oj0A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063315; 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=6uHKlC/q8J8fuulcZaDzwTuqx+Yhv6ldCkMyGrf0Ssw=; b=MrHxAophbfkW09AKn1keLeTyUZDHS+l/Amavp2ecZ0Rs9+0wJ+LIowqWGN/4OEmyZuzY N8PuWTLzEvjPBfqNqHiG0FekjghTj2HR58DLXHozw3BD5umpM8w7/ZYux/V7NBGyR4Jn/ Q3NvLT1EympJPUrw3oGvA8nUHDUj+iq1ZEf1bh+P1i9CtokkKZcojUXfzkvXpqlVbC+R0 1UFLHkbw8l8EHOgKNyRrcIoXE9+zvbvQUHAfestYv0aRWbZTRwjkNii3RiyIWZyjVMMBD lrAqzwAzE9n4+irPpezSDJWboBHZODj0PzBjHRRyz7LGVAduVJjHKIexdDgnEnOn3mg== 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=wk9jR2nV; 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 076FD606A32C; Sat, 7 Nov 2026 14:55:15 +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=wk9jR2nV Received: by smtp.kernel.org (Postfix) with ESMTPSA id A824C1F0089F; Sat, 7 Nov 2026 14:55:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063314; bh=6uHKlC/q8J8fuulcZaDzwTuqx+Yhv6ldCkMyGrf0Ssw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=wk9jR2nVE9eOJsG4T5W36nKkhaG4AlD+/aYFzCvrDAIgNDTNfj7Kmf9SZ8vYf1l2e TRVDAdcDStsDBAjkCAZNi2wMS9LQ6kQR0ExQ80HiaUzppzXwtyRW2wS8QBiHIDoqG9 zTqYpYi6CKSPQhZcYdMPNqg1AROOF/RUr30yWU5s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Lorenzo Stoakes (ARM)" , Helge Deller , Sasha Levin Subject: [PATCH 6.18 502/869] fbdev: udlfb: check for fb_deferred_io_init() error Date: Sat, 7 Nov 2026 08:53:04 -0500 Message-ID: <20261107134910.639081213@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@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: Lorenzo Stoakes (ARM) [ Upstream commit eae055f33e41e1d3e1a7e905bdcb1e9f196ed31d ] fb_deferred_io_init() allocates deferred I/O state, populating info->fbdefio_state, or leaving it NULL if an error occurs. Currently dlfb_ops_open() ignores its return value. Therefore if an error arises in fb_deferred_io_init() (for instance, due to an allocation failure) info->fbdefio_state is left NULL. fb_open() will then dereference a NULL pointer (calling fb_deferred_io_open()) as soon as dlfb_ops_open() returns. Additionally, if the allocation of info->fbdefio itself fails, dlfb_ops_open() sets info->fbdefio to NULL and invokes fb_deferred_io_init() regardless, hitting BUG_ON(!fbdefio). Fix this by only invoking fb_deferred_io_init() if the allocation succeeded, and checking for the error. The driver already supports operating without deferred I/O, so in either case fall back to that by setting info->fbdefio to NULL. The ignored return value was introduced in commit 56c134f7f1b5 ("fbdev: Track deferred-I/O pages in pageref struct"). However, the BUG_ON() issue originates from the earlier commit 5bea1fbf9423 ("staging: udlfb: fix incorrect fb_defio implementation for multiple framebuffers"), so target that for the fix. Fixes: 5bea1fbf9423 ("staging: udlfb: fix incorrect fb_defio implementation for multiple framebuffers") Cc: stable@vger.kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Helge Deller Signed-off-by: Sasha Levin --- drivers/video/fbdev/udlfb.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c index f6da680c29eac..abaac2ed22a98 100644 --- a/drivers/video/fbdev/udlfb.c +++ b/drivers/video/fbdev/udlfb.c @@ -947,10 +947,13 @@ static int dlfb_ops_open(struct fb_info *info, int user) fbdefio->delay = DL_DEFIO_WRITE_DELAY; fbdefio->sort_pagereflist = true; fbdefio->deferred_io = dlfb_dpy_deferred_io; - } - info->fbdefio = fbdefio; - fb_deferred_io_init(info); + info->fbdefio = fbdefio; + if (fb_deferred_io_init(info)) { + kfree(fbdefio); + info->fbdefio = NULL; + } + } } dev_dbg(info->dev, "open, user=%d fb_info=%p count=%d\n", -- 2.53.0