Public bug reported: SRU Justification
[Impact] There is duplicate output on the console . LSG team identify the root cause and suggested to apply two patches below. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ad8cd1db80cc33337bdbee63c453ef6d5132474b https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e369d8227fd211be36242fc44a9dc2209e246b9a What we are hitting is exactly in the second commit's log. Ubuntu kernel also needs the following diff: diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f07367100ece..dca15e27123a 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2203,7 +2203,7 @@ static int __init console_setup(char *str) * for exacly this purpose. */ if (str[0] == 0 || strcmp(str, "null") == 0) { - __add_preferred_console("ttynull", 0, NULL, NULL); + __add_preferred_console("ttynull", 0, NULL, NULL, true); return 1; } Linux kernel: 5.4.0-1078-azure Tested in Azure Host version: 22477.1101-1-0 Image: Canonical 0002-com-ubuntu-server-arm-preview-bionic 18_04-lts 18.04.202205020 From Azure Serial Console, we can see duplicate output. Such as: [ 3.109140] Platform Keyring initialized [ 3.109140] Platform Keyring initialized [ 3.117148] Key type asymmetric registered [ 3.117148] Key type asymmetric registered [ 3.122303] Asymmetric key parser 'x509' registered [ 3.122303] Asymmetric key parser 'x509' registered [Test Plan] Microsoft tested [Where things could go wrong] The kernel log could get corrupted. [Other Info] SF: #00338148 ** Affects: linux-azure (Ubuntu) Importance: Undecided Status: Fix Released ** Affects: linux-azure (Ubuntu Focal) Importance: Medium Assignee: Tim Gardner (timg-tpi) Status: In Progress ** Package changed: linux (Ubuntu) => linux-azure (Ubuntu) ** Changed in: linux-azure (Ubuntu) Status: New => Fix Released ** Also affects: linux-azure (Ubuntu Focal) Importance: Undecided Status: New ** Changed in: linux-azure (Ubuntu Focal) Importance: Undecided => Medium ** Changed in: linux-azure (Ubuntu Focal) Status: New => In Progress ** Changed in: linux-azure (Ubuntu Focal) Assignee: (unassigned) => Tim Gardner (timg-tpi) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1976399 Title: focal/azure: The console log of ARM64 Ubuntu 18.04 has duplicate output To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-azure/+bug/1976399/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
