[Bug 1807140] Re: The last console= argument is not used by the kernel
** Tags added: cscc -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1807140 Title: The last console= argument is not used by the kernel To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1807140/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1807140] Re: The last console= argument is not used by the kernel
The information above is from a VM with a reproducer. ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1807140 Title: The last console= argument is not used by the kernel To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1807140/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1807140] Re: The last console= argument is not used by the kernel
apport information ** Tags added: apport-collected uec-images ** Description changed: I ran into a problem with the console argument handling on a physical system with a BMC (Dell R610) and also reproduced the same behavior on a QEMU/KVM VM with multiple serial ports. The kernel documentation notes that the last entry will be used for /dev/console https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-tty "What:/sys/class/tty/console/active Shows the list of currently configured console devices, like 'tty1 ttyS0'. The last entry in the file is the active device connected to /dev/console. The file supports poll() to detect virtual console switches." https://elixir.bootlin.com/linux/v4.15.18/source/kernel/printk/printk.c#L1960 "The last preferred console added will be used for kernel messages and stdin/out/err for init." The actual behavior is different and the console specified in the last console argument does not become an active one. As a result, SOL functionality is not possible to use unless only one ttyS argument is specified in the kernel command line arguments. Setting the arguments to only contain the right one results in a proper behavior and I can see rx counters increasing in /proc/tty/driver/serial for the relevant port after I type something via the BMC. $ cat /proc/cmdline BOOT_IMAGE=/vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 journalctl -k | grep ttyS Dec 03 21:42:41 ubuntu kernel: Command line: BOOT_IMAGE=/vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 Dec 03 21:42:41 ubuntu kernel: Kernel command line: BOOT_IMAGE=/vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 Dec 03 21:42:41 ubuntu kernel: console [ttyS0] enabled Dec 03 21:42:41 ubuntu kernel: 00:02: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A Dec 03 21:42:41 ubuntu kernel: 00:03: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a 16550A Dec 03 21:42:41 ubuntu kernel: tty ttyS3: hash matches Full dmesg: http://paste.ubuntu.com/p/bV2pDc4Hdw/ $ cat /sys/class/tty/console/active ttyS0 tty0 $ sudo cat /proc/tty/driver/serial serinfo:1.0 driver revision: 0: uart:16550A port:03F8 irq:4 tx:78 rx:0 RTS|DTR 1: uart:16550A port:02F8 irq:3 tx:0 rx:0 CTS|DSR|CD 2: uart:unknown port:03E8 irq:4 3: uart:unknown port:02E8 irq:3 # ... ~~~ GRUB setttings: # the ones that override /etc/default/grub $ cat /etc/default/grub.d/50-curtin-settings.cfg cat: cat: No such file or directory GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200 console=ttyS1,115200" # disable grub os prober that might find other OS installs. GRUB_DISABLE_OS_PROBER=true GRUB_TERMINAL=console /etc/default/grub: https://paste.ubuntu.com/p/sdWQrY7JwN/ # grub.cfg: http://paste.ubuntu.com/p/zKGTqDh6sR/ # two entries, both with the proper arg and properly sent to the kernel cmdline based on /proc/cmdline grep ttyS grub.cfg linux /vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 linux/vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 ~~~ I managed to reproduce the exact same behavior on a VM with multiple 8250 serial ports. ubuntu@maas-vhost5:~$ cat /sys/class/tty/console/active ttyS0 ubuntu@maas-vhost5:~$ cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-4.15.0-42-generic root=UUID=a60217c2-6752-4c69-afb9-55f86a2b6c1d ro console=ttyS0,115200 console=ttyS2,115200 console=ttyS1,115200 ubuntu@maas-vhost5:~$ grep -RP ttyS /boot/grub/grub.cfg linux /boot/vmlinuz-4.15.0-42-generic root=UUID=a60217c2-6752-4c69-afb9-55f86a2b6c1d ro console=ttyS0,115200 console=ttyS2,115200 console=ttyS1,115200 linux/boot/vmlinuz-4.15.0-42-generic root=UUID=a60217c2-6752-4c69-afb9-55f86a2b6c1d ro console=ttyS0,115200 console=ttyS2,115200 console=ttyS1,115200 linux/boot/vmlinuz-4.15.0-39-generic root=UUID=a60217c2-6752-4c69-afb9-55f86a2b6c1d ro console=ttyS0,115200 console=ttyS2,115200 console=ttyS1,115200 # changed to the following config with only ttyS1 present: ubuntu@maas-vhost5:~$ grep -RP ttyS /boot/grub/grub.cfg linux /boot/vmlinuz-4.15.0-42-generic root=UUID=a60217c2-6752-4c69-afb9-55f86a2b6c1d ro console=ttyS1,115200 linux/boot/vmlinuz-4.15.0-42-generic root=UUID=a60217c2-6752-4c69-afb9-55f86a2b6c1d ro console=ttyS1,115200 linux/boot/vmlinuz-4.15.0-39-generic root=UUID=a60217c2-6752-4c69-afb9-55f86a2
[Bug 1807140] Re: The last console= argument is not used by the kernel
** Description changed: I ran into a problem with the console argument handling on a physical system with a BMC (Dell R610) and also reproduced the same behavior on a QEMU/KVM VM with multiple serial ports. - The kernel documentation notes that the last entry will + The kernel documentation notes that the last entry will be used for /dev/console https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-tty "What:/sys/class/tty/console/active - Shows the list of currently configured console devices, like 'tty1 ttyS0'. The last entry in the file is the active device connected to /dev/console. - The file supports poll() to detect virtual console switches." + Shows the list of currently configured console devices, like 'tty1 ttyS0'. The last entry in the file is the active device connected to /dev/console. + The file supports poll() to detect virtual console switches." https://elixir.bootlin.com/linux/v4.15.18/source/kernel/printk/printk.c#L1960 "The last preferred console added will be used for kernel messages and stdin/out/err for init." The actual behavior is different and the console specified in the last console argument does not become an active one. As a result, SOL functionality is not possible to use unless only one ttyS argument is specified in the kernel command line arguments. Setting the arguments to only contain the right one results in a proper behavior and I can see rx counters increasing in /proc/tty/driver/serial for the relevant port after I type something via the BMC. - $ cat /proc/cmdline + $ cat /proc/cmdline BOOT_IMAGE=/vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 journalctl -k | grep ttyS Dec 03 21:42:41 ubuntu kernel: Command line: BOOT_IMAGE=/vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 Dec 03 21:42:41 ubuntu kernel: Kernel command line: BOOT_IMAGE=/vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 Dec 03 21:42:41 ubuntu kernel: console [ttyS0] enabled Dec 03 21:42:41 ubuntu kernel: 00:02: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A Dec 03 21:42:41 ubuntu kernel: 00:03: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a 16550A Dec 03 21:42:41 ubuntu kernel: tty ttyS3: hash matches Full dmesg: http://paste.ubuntu.com/p/bV2pDc4Hdw/ $ cat /sys/class/tty/console/active ttyS0 tty0 $ sudo cat /proc/tty/driver/serial serinfo:1.0 driver revision: 0: uart:16550A port:03F8 irq:4 tx:78 rx:0 RTS|DTR 1: uart:16550A port:02F8 irq:3 tx:0 rx:0 CTS|DSR|CD 2: uart:unknown port:03E8 irq:4 3: uart:unknown port:02E8 irq:3 # ... - ~~~ GRUB setttings: # the ones that override /etc/default/grub $ cat /etc/default/grub.d/50-curtin-settings.cfg cat: cat: No such file or directory GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200 console=ttyS1,115200" # disable grub os prober that might find other OS installs. GRUB_DISABLE_OS_PROBER=true GRUB_TERMINAL=console /etc/default/grub: https://paste.ubuntu.com/p/sdWQrY7JwN/ # grub.cfg: http://paste.ubuntu.com/p/zKGTqDh6sR/ # two entries, both with the proper arg and properly sent to the kernel cmdline based on /proc/cmdline - grep ttyS grub.cfg - linux /vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 - linux /vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 - + grep ttyS grub.cfg + linux /vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 + linux/vmlinuz-4.15.0-42-generic root=UUID=580a3c58-1040-4c7d-b94f-93230874caf5 ro console=tty0 console=ttyS0,115200 console=ttyS1,115200 ~~~ - - I managed to reproduce the exact same behavior on a VM with multiple 8250 serial ports. + I managed to reproduce the exact same behavior on a VM with multiple + 8250 serial ports. ubuntu@maas-vhost5:~$ cat /sys/class/tty/console/active ttyS0 - ubuntu@maas-vhost5:~$ cat /proc/cmdline + ubuntu@maas-vhost5:~$ cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-4.15.0-42-generic root=UUID=a60217c2-6752-4c69-afb9-55f86a2b6c1d ro console=ttyS0,115200 console=ttyS2,115200 console=ttyS1,115200 - ubuntu@maas-vhost5:~$ grep -RP ttyS /boot/grub/grub.cfg - linux /boot/vmlinuz-4.15.0-42-generic root=UUID=a60217c2-6752-4c69-afb9-55f86a2b6c1d ro console=ttyS0,115200 console=ttyS2,115200 console=ttyS1,115200 - linux /boot/vmlinuz-4.15.0-42-generic root=UUID=a60217c2-6752-4c6
