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=1794407931; b=K3DadDgy+i/jkpgWK4FdWBAGve9uC6Rr34RDp3tTcdo4PU4jenakXknRCp3UL3YujTwO 0NerFLQXBX0I+HfOoPc6EvlM0Wu2tKhxP08P+KMzeqsogKfNlFpznuMh2JfpbeMsL8Wj+ ae5em4uPfbGOFzAA3/FVXCVBDhC5SEMRmzKH9cvzUQykA2PbeFgbdYK0V0mFJULcyg1We lfabU7brIAttxoBINwrZsqqULmcpiOjfgGFiBYv9aOzfYgWjJIgfSkCxAxNQtz9Y8Q9q4 xA0jgnV4N9k7Om+61Vt/F1NUFrzyhO6a1RRXGLMmoNUtlVfYXGx2SZEU7xIiPEqpZfA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794407931; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=rYa6Vj482aOsAT1swBjVHBxJ66Ekod+nCxHVhlJVP6o=; b=ItxKRJOf2bp8JJ8zqjxQZWOZ35eTrEahJreqVXcWyZtpguUT8xVeWZDCgLCHxeaw9s9w HjKtt/9pbp7Iy8sUs5gQ0c5MSP+FDE7bA858BS+X5EbX+dDZyJI6+yoPGNx7VOS+PAfov Ec9HJ3ZpzVE5FotagEoKF4A50D7NavPJPQ0HQZ51uoXE7+PuaLW84HsJxhB2gld/F5QwL onQvXZpOPkbuRm9lhmyc7uDEt3MF6on+mqR1XbcwUbygp9MzriV6N/F7pGNYHIZlmmSqc DwyEeGY3NlIYjxl1N95FfRYyoIVPsNatpysvuwwN/d2evba6QbvbUy9nQR8EAXXSGTw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=oBGjlNHt; 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 96BFA606A32A for ; Wed, 11 Nov 2026 14:38:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=oBGjlNHt Received: by smtp.kernel.org (Postfix) with ESMTPSA id 908701F00A05; Wed, 11 Nov 2026 14:38:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794407931; bh=rYa6Vj482aOsAT1swBjVHBxJ66Ekod+nCxHVhlJVP6o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=oBGjlNHtijskBTBq2sraVdZwvWLaFnVZhIKwiJk6wvwbXfrPUdjlq8AcYqPlxpZzv stbj2WftmNHQd/nxGGC3KlCJ2E7GfoDFP/oFAAEBtcwRN4Q95pPSDp4iTjcWtpH/+a idllULOiDWUJn+Zud9OAy0/H3W9cN0JdA0wgUHLdKKkMyxkUk7f/hYEPJ0ajlONsmb 73oLH5cnZowE9Hs0pdj/IzWkLQyVZ0z38Fvjmgw2iMtGqvPudj50xVViLUfbrYMqg0 c+n2YpG86I0NUnunnjvaJi0y94Uf+wcGG/lvyjeC42wPK4ItQtN6he3r5bxNuDFgCA CuawLGQUFeECg== From: Sasha Levin To: stable@vger.kernel.org Cc: "Lorenzo Stoakes (ARM)" , Helge Deller , Sasha Levin Subject: [PATCH 5.10.y] fbdev: udlfb: check for fb_deferred_io_init() error Date: Wed, 11 Nov 2026 09:38:49 -0500 Message-ID: <20261111143826.2357715-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107062159-failed-5.10-eae055f33e41@kernel.org> References: <20261107062159-failed-5.10-eae055f33e41@kernel.org> 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 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 [ sashal: Omitted fb_deferred_io_init() error handling because the older API returns void and cannot fail. ] Signed-off-by: Sasha Levin --- drivers/video/fbdev/udlfb.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c index 23097d190e0b1..d3e7c8f6ae7eb 100644 --- a/drivers/video/fbdev/udlfb.c +++ b/drivers/video/fbdev/udlfb.c @@ -1006,10 +1006,10 @@ static int dlfb_ops_open(struct fb_info *info, int user) if (fbdefio) { fbdefio->delay = DL_DEFIO_WRITE_DELAY; fbdefio->deferred_io = dlfb_dpy_deferred_io; - } - info->fbdefio = fbdefio; - fb_deferred_io_init(info); + info->fbdefio = fbdefio; + fb_deferred_io_init(info); + } } dev_dbg(info->dev, "open, user=%d fb_info=%p count=%d\n", -- 2.53.0