From: Oliver Neukum <oneukum@suse.com>
Date: Mon, 9 Feb 2026 14:20:48 +0000 (+0100)
Subject: usb: mdc800: handle signal and read racing
X-Git-Tag: v7.0-rc4~14^2~29
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2d6d260e9a3576256fe9ef6d1f7930c9ec348723;p=thirdparty%2Flinux.git

usb: mdc800: handle signal and read racing

If a signal arrives after a read has partially completed,
we need to return the number of bytes read. -EINTR is correct
only if that number is zero.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20260209142048.1503791-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/usb/image/mdc800.c b/drivers/usb/image/mdc800.c
index 8d8e79afa600..e76a502fa9da 100644
--- a/drivers/usb/image/mdc800.c
+++ b/drivers/usb/image/mdc800.c
@@ -707,7 +707,7 @@ static ssize_t mdc800_device_read (struct file *file, char __user *buf, size_t l
 		if (signal_pending (current)) 
 		{
 			mutex_unlock(&mdc800->io_lock);
-			return -EINTR;
+			return len == left ? -EINTR : len-left;
 		}
 
 		sts=left > (mdc800->out_count-mdc800->out_ptr)?mdc800->out_count-mdc800->out_ptr:left;