This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:
apport-collect 1895550 and then change the status of the bug to 'Confirmed'. If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'. This change has been made by an automated script, maintained by the Ubuntu Kernel Team. ** Changed in: linux (Ubuntu) Status: New => Incomplete -- 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/1895550 Title: Ubuntu 18.04.5 release for Raspberry Pi 4 does not boot Status in linux package in Ubuntu: Incomplete Bug description: I have a Raspberry Pi 4 Model B. I downloaded and flashed the image `ubuntu-18.04.5-preinstalled-server-arm64+raspi4.img` (md5 = b75105bf4e27cbcc44dc471becc8907d), which is the currently recommended release for this hardware on the Ubuntu.com website. Booting reaches this point where it tries to do something with the SD card, then fails: [ 4.352613] random: fast init done [ 4.414200] mmc0: new ultra high speed DDR50 SDHC card at address aaaa [ 4.423077] mmcblk0: mmc0:aaaa SC32G 29.7 GiB [ 4.431244] mmc1: new high speed SDIO card at address 0001 [ 4.437267] mmcblk0: p1 p2 Afterwards, about once per minute, it outputs an error message like this: [ 28.006460] rcu: INFO: rcu_sched detected stalls on CPUs/tasks: [ 28.012484] rcu: 1-...0: (7 ticks this GP) idle=1d6/1/0x4000000000000000 softirq=80/81 fqs=7 [ 28.021231] (detected by 3, t=5893 jiffies, g=-379, q=2) [ 28.026710] Task dump for CPU 1: [ 28.029984] swapper/0 R running task 0 1 0 0x0000002a [ 28.037143] Call trace: [ 28.039636] __switch_to+0xcc/0x208 [ 28.043179] console_unlock+0x4f8/0x600 [ 28.047076] rcu: rcu_sched kthread starved for 1001 jiffies! g-379 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=3 [ 28.057405] rcu: RCU grace-period kthread stack dump: [ 28.062529] rcu_sched I 0 10 2 0x00000028 [ 28.068098] Call trace: [ 28.070580] __switch_to+0xcc/0x208 [ 28.074123] __schedule+0x2c4/0x7b0 [ 28.077663] schedule+0x38/0xa8 [ 28.080851] schedule_timeout+0x1a0/0x378 [ 28.084920] rcu_gp_kthread+0x688/0xa10 [ 28.088813] kthread+0x124/0x128 [ 28.092089] ret_from_fork+0x10/0x1c I made 2 or 3 attempts at this and each time it failed in the same way. The only modifications I made to the filesystem were to the `user- data` and `network-config` files for headless setup. I do not believe these modifications are relevant. I downloaded and flashed the previous release, `ubuntu-18.04.4 -preinstalled-server-arm64+raspi4.img`, and that release booted successfully. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1895550/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp