From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 461AE3431E3; Tue, 16 Dec 2025 11:27:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765884470; cv=none; b=WNpUaTzaC+NMmoQ8l2+xZG8nlhJw9q7dYO8J/KoX/TpnSVSya2jrcG6LJiMfv7yPqEym69xLx/fsxjDmhQIT7hHmpUlCDG+ubgv9a5WXmXq8GoYRmhk8Dzo/KSVeKcIy1/tvHVtWn83CWyTBc6lTd3NFgcud4pNZC16SDJ81qCU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765884470; c=relaxed/simple; bh=H+Vqmm7LJCqR+VPhv8z6BbvM2t0VflUqaICQnc1i24E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MBO4aHbp1tbVR676wFkx8YnZTxfg9TsIvjsantISM6JZ6CAs71Ds43lO0BfpI0bivML/UN+T3gZ/C31fex91b75zYgcZcrb/vPv3Bxs3BJv+m8mmicw81+UrFYkUnrjUpaAcm0m3SxG8PGw9kogrb4oGpMQfmhwmp+Qt2o5lXws= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=juWw19Wl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="juWw19Wl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE5BDC4CEF1; Tue, 16 Dec 2025 11:27:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1765884470; bh=H+Vqmm7LJCqR+VPhv8z6BbvM2t0VflUqaICQnc1i24E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=juWw19Wlyvc8EIN68lCGL9v0FXCGQYOBhhsZKN9qG6v6lod2v+Cqj42iV/jvPLs2m 3n+Vb8b8um8w6AW/cPBudXBHPEQbs4arhEVLaZT3Jvpfipqq72ZsFllqqYt6+Dwe9O C7iXk3PNbjJ1s7rQeP1sjMtALbE5yWxc7pjdkPnI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Oliver Neukum , Sasha Levin Subject: [PATCH 6.12 202/354] usb: chaoskey: fix locking for O_NONBLOCK Date: Tue, 16 Dec 2025 12:12:49 +0100 Message-ID: <20251216111328.237398500@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251216111320.896758933@linuxfoundation.org> References: <20251216111320.896758933@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oliver Neukum [ Upstream commit a2fa8a12e6bc9d89c0505b8dd7ae38ec173d25de ] A failure to take a lock with O_NONBLOCK needs to result in -EAGAIN. Change it. Fixes: 66e3e591891da ("usb: Add driver for Altus Metrum ChaosKey device (v2)") Signed-off-by: Oliver Neukum Link: https://patch.msgid.link/20251030093918.2248104-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/misc/chaoskey.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c index 225863321dc47..45cff32656c6e 100644 --- a/drivers/usb/misc/chaoskey.c +++ b/drivers/usb/misc/chaoskey.c @@ -444,9 +444,19 @@ static ssize_t chaoskey_read(struct file *file, goto bail; mutex_unlock(&dev->rng_lock); - result = mutex_lock_interruptible(&dev->lock); - if (result) - goto bail; + if (file->f_flags & O_NONBLOCK) { + result = mutex_trylock(&dev->lock); + if (result == 0) { + result = -EAGAIN; + goto bail; + } else { + result = 0; + } + } else { + result = mutex_lock_interruptible(&dev->lock); + if (result) + goto bail; + } if (dev->valid == dev->used) { result = _chaoskey_fill(dev); if (result < 0) { -- 2.51.0