Hello, The kernel panic occurs very early in the boot sequence, even before the root fs is mounted to capture the log. Here is the kenrel backtrace :
[ 1.251773] Kernel panic - not syncing: Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer [ 1.253440] CPU: 2 PID: 212 Comm: systemd-udevd Not tainted 5.13.0-23-generic #23-Ubuntu [ 1.255022] Hardware name: Scaleway SCW-ENT1-S, BIOS 0.0.0 02/06/2015 [ 1.256228] Call Trace: [ 1.256697] show_stack+0x52/0x58 [ 1.257355] dump_stack+0x7d/0x9c [ 1.257989] panic+0x101/0x2e3 [ 1.258821] swiotlb_tbl_map_single.cold+0x57/0x7c [ 1.259750] swiotlb_map+0x61/0x240 [ 1.260428] dma_direct_map_page+0x115/0x1a0 [ 1.261255] dma_map_page_attrs+0x35/0x50 [ 1.262016] vring_map_one_sg+0x4c/0x50 [ 1.262787] virtqueue_add_split+0x23c/0x4a0 [ 1.263427] virtqueue_add_inbuf+0x48/0x50 [ 1.263909] virtscsi_kick_event.isra.0+0x8b/0xd0 [virtio_scsi] [ 1.264616] virtscsi_probe+0x31e/0x33b [virtio_scsi] [ 1.265216] virtio_dev_probe+0x163/0x220 [ 1.265683] really_probe+0x24b/0x4c0 [ 1.266134] driver_probe_device+0xf0/0x160 [ 1.266647] device_driver_attach+0xab/0xb0 [ 1.267188] __driver_attach+0xb2/0x140 [ 1.267648] ? device_driver_attach+0xb0/0xb0 [ 1.268163] bus_for_each_dev+0x7e/0xc0 [ 1.268620] driver_attach+0x1e/0x20 [ 1.269061] bus_add_driver+0x135/0x1f0 [ 1.269516] driver_register+0x95/0xf0 [ 1.269957] ? 0xffffffffc038e000 [ 1.270344] register_virtio_driver+0x20/0x30 [ 1.270885] init+0x8d/0x1000 [virtio_scsi] [ 1.271380] ? 0xffffffffc038e000 [ 1.271762] do_one_initcall+0x48/0x1d0 [ 1.272213] ? kmem_cache_alloc_trace+0xfb/0x240 [ 1.272759] do_init_module+0x62/0x290 [ 1.273199] load_module+0xa8f/0xb10 [ 1.273620] __do_sys_finit_module+0xc2/0x120 [ 1.274155] __x64_sys_finit_module+0x18/0x20 [ 1.274680] do_syscall_64+0x61/0xb0 [ 1.275118] ? syscall_exit_to_user_mode+0x27/0x50 [ 1.275667] ? __x64_sys_newfstatat+0x1c/0x20 [ 1.276177] ? do_syscall_64+0x6e/0xb0 [ 1.276614] ? ksys_read+0x67/0xe0 [ 1.277049] ? exit_to_user_mode_prepare+0x37/0xb0 [ 1.277614] ? syscall_exit_to_user_mode+0x27/0x50 [ 1.278180] ? __x64_sys_read+0x19/0x20 [ 1.278653] ? do_syscall_64+0x6e/0xb0 [ 1.279116] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 1.279709] RIP: 0033:0x7fe040ccd94d [ 1.280140] Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b3 64 0f 00 f7 d8 64 89 01 48 [ 1.282337] RSP: 002b:00007ffe2399a6d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 [ 1.283252] RAX: ffffffffffffffda RBX: 0000562e8ab7a030 RCX: 00007fe040ccd94d [ 1.284077] RDX: 0000000000000000 RSI: 00007fe040e61441 RDI: 0000000000000005 [ 1.284910] RBP: 0000000000020000 R08: 0000000000000000 R09: 00007ffe2399a810 [ 1.285754] R10: 0000000000000005 R11: 0000000000000246 R12: 00007fe040e61441 [ 1.286594] R13: 0000562e8ab79ef0 R14: 0000562e8abd1c50 R15: 0000562e8abd4400 [ 1.288517] Kernel Offset: 0x25a00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 1.289795] ---[ end Kernel panic - not syncing: Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer ]--- - -- 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/1955655 Title: kernel-5.13.0-23-generic : Unable to boot when Secure Encrypted Virtualization( SEV) is enabled without setting swiotlb boot param Status in linux package in Ubuntu: Confirmed Bug description: While investigating LP: #1955395 by using the -generic kernel image, it appeared that it is impossible to boot the kernel unless the boot parameter swiotlb is set to 512M (swiotlb=262144). Wnen not set, the kernel tries to adjust the bounce buffer to 1024Mb it fails and later trigger a kernel panic with the following trace : $ grep TLB /tmp/console.log [ 0.003665] software IO TLB: SWIOTLB bounce buffer size adjusted to 1024MB [ 0.034219] kvm-guest: KVM setup pv remote TLB flush [ 0.037063] software IO TLB: Cannot allocate buffer [ 0.223009] Last level iTLB entries: 4KB 512, 2MB 255, 4MB 127 [ 0.223634] Last level dTLB entries: 4KB 512, 2MB 255, 4MB 127, 1GB 0 [ 0.297424] HugeTLB registered 1.00 GiB page size, pre-allocated 0 pages [ 0.297424] HugeTLB registered 2.00 MiB page size, pre-allocated 0 pages [ 1.018860] PCI-DMA: Using software bounce buffering for IO (SWIOTLB) [ 1.019552] software IO TLB: No low mem [ 1.451497] Kernel panic - not syncing: Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer [ 1.491589] ---[ end Kernel panic - not syncing: Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer ]--- The SWIOTLB adjustment comes from the following kernel commit : https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e998879d4fb7991856916972168cf27c0d86ed12 For some reason, the LowMem allocation fails (as seen by the "software IO TLB: No low mem" msg),hence the SWIOTLB adjustment cannot be completed. When booting with the swiotlb=262144 value, we get the following output : $ grep TLB /tmp/console.log [ 0.050908] kvm-guest: KVM setup pv remote TLB flush [ 0.308896] Last level iTLB entries: 4KB 512, 2MB 255, 4MB 127 [ 0.309494] Last level dTLB entries: 4KB 512, 2MB 255, 4MB 127, 1GB 0 [ 0.373162] HugeTLB registered 1.00 GiB page size, pre-allocated 0 pages [ 0.373162] HugeTLB registered 2.00 MiB page size, pre-allocated 0 pages [ 1.071136] PCI-DMA: Using software bounce buffering for IO (SWIOTLB) [ 1.071837] software IO TLB: mapped [mem 0x000000005bebe000-0x000000007bebe000] (512MB) [ 1.529804] software IO TLB: Memory encryption is active and system is using DMA bounce buffers For comparaison, the Fedora 34 kernel (5.15.4-101.fc34.x86_64) with the same adjustment mechanism does correctly adjust the SWIOTLB bounce buffer, without the need to set the swiotlb= value at boot time. The SWIOTLB buffer adjustment has been introduced in kernel 5.11. We can make SEV enabled resources available for testing if needed. ...Louis --- ProblemType: Bug AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Dec 23 13:32 seq crw-rw---- 1 root audio 116, 33 Dec 23 13:32 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.20.11-0ubuntu74 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: CRDA: N/A CasperMD5CheckResult: unknown DistroRelease: Ubuntu 22.04 IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig' Lsusb: Error: command ['lsusb'] failed with exit code 1: Lsusb-t: Lsusb-v: Error: command ['lsusb', '-v'] failed with exit code 1: MachineType: Scaleway SCW-ENT1-S Package: linux (not installed) PciMultimedia: ProcEnviron: TERM=screen PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=C.UTF-8 SHELL=/bin/bash ProcFB: ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.13.0-23-generic root=UUID=1f577236-6bf2-48ef-998a-ba45f71aca7f ro console=tty1 console=ttyS0 swiotlb=262144 ProcVersionSignature: Ubuntu 5.13.0-23.23-generic 5.13.19 RelatedPackageVersions: linux-restricted-modules-5.13.0-23-generic N/A linux-backports-modules-5.13.0-23-generic N/A linux-firmware N/A RfKill: Error: [Errno 2] No such file or directory: 'rfkill' Tags: jammy uec-images Uname: Linux 5.13.0-23-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: N/A _MarkForUpload: True dmi.bios.date: 02/06/2015 dmi.bios.release: 0.0 dmi.bios.vendor: EFI Development Kit II / OVMF dmi.bios.version: 0.0.0 dmi.chassis.type: 1 dmi.chassis.vendor: QEMU dmi.chassis.version: pc-q35-3.0 dmi.modalias: dmi:bvnEFIDevelopmentKitII/OVMF:bvr0.0.0:bd02/06/2015:br0.0:svnScaleway:pnSCW-ENT1-S:pvrpc-q35-3.0:cvnQEMU:ct1:cvrpc-q35-3.0:sku: dmi.product.name: SCW-ENT1-S dmi.product.version: pc-q35-3.0 dmi.sys.vendor: Scaleway To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1955655/+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
