Copying big files to a mounted Synology NAS crashes the NAS

[pjotter]

Situation:

OS: Xubuntu 22.04.3
Kernel version: 6.2.0-39-generic
Network driver: r8169
Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 01)
NAS model: Synology DiskStation DS223

The problem:

On a freshly installed Xubuntu 22.04.3, I use a cifs-mounted Synology DS223 NAS. It mounts without any problems and at first glance everything seems to be working fine, until you start uploading large(r) files (200MB+) to the NAS. The NAS will then randomly and for unknown reasons crash or halt, causing the Xubuntu OS to halt or crash in turn. It does so in any application (Thunar, copying files in bash, tuxcommander etc). So, this problem doesn't seem to be application-related. I tried mounting the NAS with different/additional mount-options and tried several network settings and even checked the physical cables but nothing had any effect.

The solution:

Eventually, I managed to trace the problem to my network device and I replaced the r8169 driver for the r8168 version. This immediately solved my problem. Now, copying from-and-to the mounted NAS works as expected.

Even though my problem is solved by installing the r8168 version of the driver, there probably still remains a bug in the default r8169 driver that causes this problem with my current setup.

Note: The r8169 driver is integrated in the kernel whereas the r8168 driver can be installed by installing the r8168-dkms package and disabling (blacklisting) the r8169 driver in the kernel.