Test kernels with the fix are available in: https://people.canonical.com/~mfo/lp1867916/
-- 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/1867916 Title: Regression in kernel 4.15.0-91 causes kernel panic with Bcache Status in Linux: Confirmed Status in linux package in Ubuntu: Fix Committed Status in linux source package in Xenial: In Progress Status in linux source package in Bionic: In Progress Status in linux source package in Eoan: In Progress Status in linux source package in Focal: In Progress Status in linux source package in Groovy: Won't Fix Bug description: [Impact] * Users of bcache who manually specified a block size greater than the page size when creating the device with 'make-bcache' started to hit a kernel BUG/oops after kernel upgrades. (This is not widely used.) * The issue has been exposed with commit ad6bf88a6c19 ("block: fix an integer overflow in logical block size") because it increased the range of values accepted as logical block size, which used to overflow to zero, and thus receive a default of 512 via block layer. * The issue existed previously, but with fewer values exposed (e.g. 8k, 16k, 32k); the regression reports happened with larger values (512k) for RAID stripes. [Fix] * The upstream commit dcacbc1242c7 ("bcache: check and adjust logical block size for backing devices") checks the block size and adjusts it if needed, to the value of the underlying device's logical block size. * It is merged as of v5.8-rcN, and sent to v5.7 stable. [Test Case] * Run make-bcache with block size greater than page size. $ sudo make-bcache --bdev $DEV --block 8k * Expected results: bcache device registered; no BUG/oops. * Details steps on comment #43. [Regression Potential] * Restricted to users who specify a bcache block size greater than page size. * Regressions could theoretically manifest on bcache device probe/register, if the underlying device's logical block size for whatever triggers issues not seen previously with the overflow/default 512 bytes. [Other Info] * Unstable has the patch on both master/master-5.7. * Groovy should get it on rebase. [Original Bug Description] After upgrading from kernel 4.15.0-88 to 4.15.0-91 one of our systems does not boot any longer. It always crashes during boot with a kernel panic. I suspect that this crash might be related to Bcache because this is the only one of our systems where we use Bcache and the kernel panic appears right after Bcache initialization. I already checked that this bug still exists in the 4.15.0-92.93 kernel from proposed. Unfortunately, I cannot do a bisect because this is a critical production system and we do not have any other system with a similar configuration. I attached a screenshot with the trace of the kernel panic. The last message that appears before the kernel panic (or rather the last one that I can see - there is a rather long pause between that message and the panic and I cannot scroll up far enough to ensure that there are no other messages in between) is: bcache: register_bcache() error /dev/dm-0: device already registered When booting with kernel 4.15.0-88 that does not have this problem, the next message is bcache: register_bcache() error /dev/dm-12: device already registered (emitting change event) After that the next message is: Begin: Loading essential drivers ... done This message also appears after the kernel panic, but the boot process stalls and the system can only be recovered by doing a hardware reset. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-88-generic 4.15.0-88.88 ProcVersionSignature: Ubuntu 4.15.0-88.88-generic 4.15.18 Uname: Linux 4.15.0-88-generic x86_64 AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Mar 17 21:08 seq crw-rw---- 1 root audio 116, 33 Mar 17 21:08 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay': 'aplay' ApportVersion: 2.20.9-0ubuntu7.11 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord': 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: Date: Wed Mar 18 12:55:18 2020 HibernationDevice: RESUME=UUID=40512ea2-9fce-40f5-8362-5daf955cc26a InstallationDate: Installed on 2013-07-02 (2450 days ago) InstallationMedia: Ubuntu-Server 12.04.2 LTS "Precise Pangolin" - Release amd64 (20130214) MachineType: HP ProLiant DL160 G6 PciMultimedia: ProcFB: 0 mgadrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.15.0-88-generic root=/dev/mapper/vg0-root ro nosmt nomdmonddf nomdmonisw nomdmonddf nomdmonisw nomdmonddf nomdmonisw nomdmonddf nomdmonisw nomdmonddf nomdmonisw RelatedPackageVersions: linux-restricted-modules-4.15.0-88-generic N/A linux-backports-modules-4.15.0-88-generic N/A linux-firmware 1.173.16 RfKill: Error: [Errno 2] No such file or directory: 'rfkill': 'rfkill' SourcePackage: linux UpgradeStatus: Upgraded to bionic on 2018-09-23 (541 days ago) dmi.bios.date: 11/06/2009 dmi.bios.vendor: HP dmi.bios.version: O33 dmi.chassis.asset.tag: 0191525 dmi.chassis.type: 23 dmi.chassis.vendor: HP dmi.modalias: dmi:bvnHP:bvrO33:bd11/06/2009:svnHP:pnProLiantDL160G6:pvr:cvnHP:ct23:cvr: dmi.product.name: ProLiant DL160 G6 dmi.sys.vendor: HP To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1867916/+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
