Comment 13 for bug 1955655

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 ]---
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