Hi Heiko, I had a look at the changes between 5.15.0-86-generic and 5.15.0-88-generic, and there are the following cifs commits:
ubuntu-jammy $ git log --grep "cifs" --oneline Ub untu-5.15.0-86.96..Ubuntu-5.15.0-88.98 c92787866aa8 cifs: if deferred close is disabled then close files immediately 5c684782dfb6 ksmbd: remove internal.h include 015222ee0044 cifs: use fs_context for automounts 0ba530127927 cifs: missing directory in MAINTAINERS file a6f0ea8bffe0 keys: Fix linking a duplicate key to a keyring's assoc_array The interesting one is "cifs: use fs_context for automounts" in particular, which you have already noted removes the cifs_dfs_do_mount() function and spreads the logic into cifs_dfs_do_automount(). It seems "cifs: use fs_context for automounts" was introduced in 6.2-rc1 upstream, and was brought into our kernel due to it being a dependency of "cifs: if deferred close is disabled then close files immediately" which was recently included in upstream stable. I have built you a test kernel based on 5.15.0-88-generic with the following two commits reverted: commit df9d70c18616760c6504b97fec66b6379c172dbb Author: Bharath SM <[email protected]> Date: Fri Jul 7 15:29:01 2023 +0000 Subject: cifs: if deferred close is disabled then close files immediately Link: https://github.com/torvalds/linux/commit/df9d70c18616760c6504b97fec66b6379c172dbb commit 9fd29a5bae6e8f94b410374099a6fddb253d2d5f Author: Paulo Alcantara <[email protected]> Date: Tue Oct 4 18:41:20 2022 -0300 Subject: cifs: use fs_context for automounts Link: https://github.com/torvalds/linux/commit/9fd29a5bae6e8f94b410374099a6fddb253d2d5f Please note this package is NOT SUPPORTED by Canonical, and is for TESTING PURPOSES ONLY. ONLY Install in a dedicated test environment. Instructions to install (On a Jammy system): 1) sudo add-apt-repository ppa:mruffell/lp2043118-test 2) sudo apt update 3) sudo apt install linux-image-unsigned-5.15.0-88-generic linux-modules-5.15.0-88-generic linux-modules-extra-5.15.0-88-generic linux-headers-5.15.0-88-generic 4) sudo reboot 5) uname -rv 5.15.0-88-generic #98+TEST2043118v20231110b1-Ubuntu SMP Fri Nov 10 10:00:22 UTC 2023 If you are asked to abort removal of the currently running kernel, say no. Can you let me know if the test kernel works? If it does, then we at least know the commits which caused the issue. From there we can decide to revert in the next Ubuntu kernel release, or see if the current upstream is broken and come up with a fix instead. Could you also try 6.6-rc5, like Timo suggested? https://kernel.ubuntu.com/mainline/v6.6-rc5/ $ wget https://kernel.ubuntu.com/mainline/v6.6-rc5/amd64/linux-image-unsigned-6.6.0-060600rc5-generic_6.6.0-060600rc5.202310081731_amd64.deb $ wget https://kernel.ubuntu.com/mainline/v6.6-rc5/amd64/linux-modules-6.6.0-060600rc5-generic_6.6.0-060600rc5.202310081731_amd64.deb $ sudo dpkg -i ./linux-* $ sudo reboot Thanks, Matthew -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2043118 Title: Regression CIFS mounted DFS Status in linux package in Ubuntu: New Status in linux source package in Jammy: Incomplete Bug description: On Ubuntu 22.04.3 LTS (jammy jellyfish) we mount a DFS file service using CIFS with kerberos authentication. After the kernel upgrade from 5.15.0-86-generic to 5.15.0-88-generic (exact version: 5.15.0-88.98) this stopped working. The mount seems to have worked, but files and directories are inaccessible. A non-DFS CIFS share mounted on the same client machine is not affected. In our case the filesystem is mounted using autofs with the following mapping: /dfs-share -fstype=cifs,sec=krb5,vers=3,multiuser,noserverino ://example.com/share Kernel log messages: CIFS: Attempting to mount \\example.com\share CIFS: VFS: BAD_NETWORK_NAME: \\example.com\share CIFS: VFS: Verify user has a krb5 ticket and keyutils is installed CIFS: VFS: \\CLx-Ny.EXAMPLE.COM Send error in SessSetup = -126 We confirmed that kernel version 5.15.0-88 causes this by booting different kernel versions repeatedly. When booting 5.15.0-86 everything worked properly as before. Though not familiar with kernel coding, we found changes in the source code that seem to confirm that some code dealing with DFS has changed, moved, or removed. After: git clone git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy This: git diff Ubuntu-5.15.0-86.96 Ubuntu-5.15.0-88.98 -- fs/cifs/cifs_dfs_ref.c This suggests the function cifs_dfs_do_mount() has been (re)moved. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2043118/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
