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 17007350286; Tue, 16 Dec 2025 12:24:25 +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=1765887866; cv=none; b=Zr6rAVayDxRN9bLCy6iCkXsAz0J/syKc6D47S5rmH+P928qWN8zpZaIfmuxb1c3AmnivhXF9t1ebHyTKwdllLgNio3b1Qx9yOT456Zm4NNL851lhGQyB6fnxTD94N+KyodHmCjyviMWhVqgSz5jRjvC7tmUEgogUSTYkDwPTaUQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765887866; c=relaxed/simple; bh=e7Pf0aiM7N8eQlPPup6svKtsnCBcLnPsp9hoQQirutE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sFeDMsgE6H1cw2nTdTCqjbWA9hk96wVhTZFAkApFSXaOTmm9j02XNaVUgVYR5o0/HAjblqUmF6uQ/skOaPbrSrmMOhDEHKWbyrKPD0KAMF67T9Cj+bpuiQXhkAhtAOmGW/yHymixJbt4jB70Jaz3ywGuVJ+/AiNzWR3vPq2TiC0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZQQZvzoC; 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="ZQQZvzoC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A5C7C4CEF1; Tue, 16 Dec 2025 12:24:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1765887865; bh=e7Pf0aiM7N8eQlPPup6svKtsnCBcLnPsp9hoQQirutE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZQQZvzoCyEYTMAY4IrxW0uwQfwApo7U4psyJlHsjE1zUy4HhNqXK/z3gEZ2EpKFC+ Ic9ONeiXqoSNC5uFmNS6xNlFy7JZz1CvtohCR6i0JXGT+jofM8/UoxEIddmn2e5Dry kXbMXaJ/I+8zsLHuhHVWeQDnIgzlrCYMKwgIk1Js= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Oliver Neukum , Sasha Levin Subject: [PATCH 6.18 362/614] usb: chaoskey: fix locking for O_NONBLOCK Date: Tue, 16 Dec 2025 12:12:09 +0100 Message-ID: <20251216111414.476311325@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251216111401.280873349@linuxfoundation.org> References: <20251216111401.280873349@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-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