There is a kernel OOPS in the log file:

Mar 10 18:31:57 ubuntu ubiquity: cat: 
Mar 10 18:31:57 ubuntu kernel: [ 5430.721882] cat: page allocation failure: order:6, mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0
Mar 10 18:31:57 ubuntu kernel: [ 5430.721892] CPU: 1 PID: 19513 Comm: cat Tainted: P           O      5.10.0-14-generic #15-Ubuntu
Mar 10 18:31:57 ubuntu kernel: [ 5430.721894] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
Mar 10 18:31:57 ubuntu kernel: [ 5430.721895] Call Trace:
Mar 10 18:31:57 ubuntu kernel: [ 5430.721916]  show_stack+0x52/0x58
Mar 10 18:31:57 ubuntu kernel: [ 5430.721920]  dump_stack+0x70/0x8b
Mar 10 18:31:57 ubuntu kernel: [ 5430.721924]  warn_alloc.cold+0x7b/0xdf
Mar 10 18:31:57 ubuntu kernel: [ 5430.721930]  __alloc_pages_slowpath.constprop.0+0x9e5/0xa20
Mar 10 18:31:57 ubuntu kernel: [ 5430.721931]  ? get_page_from_freelist+0x180/0x330
Mar 10 18:31:57 ubuntu kernel: [ 5430.721933]  __alloc_pages_nodemask+0x2e0/0x310
Mar 10 18:31:57 ubuntu kernel: [ 5430.721936]  alloc_pages_current+0x87/0x110
Mar 10 18:31:57 ubuntu kernel: [ 5430.721939]  kmalloc_order+0x2c/0x90
Mar 10 18:31:57 ubuntu kernel: [ 5430.721940]  kmalloc_order_trace+0x1d/0x80
Mar 10 18:31:57 ubuntu kernel: [ 5430.721942]  __kmalloc+0x20b/0x240
Mar 10 18:31:57 ubuntu kernel: [ 5430.721945]  ? lru_cache_add_inactive_or_unevictable+0x28/0xa0
Mar 10 18:31:57 ubuntu kernel: [ 5430.721949]  proc_sys_call_handler+0xb9/0x230
Mar 10 18:31:57 ubuntu kernel: [ 5430.721951]  ? handle_pte_fault+0x22b/0x260
Mar 10 18:31:57 ubuntu kernel: [ 5430.721953]  proc_sys_read+0x10/0x20
Mar 10 18:31:57 ubuntu kernel: [ 5430.721955]  new_sync_read+0x10d/0x190
Mar 10 18:31:57 ubuntu kernel: [ 5430.721957]  vfs_read+0x15a/0x1c0
Mar 10 18:31:57 ubuntu kernel: [ 5430.721960]  ksys_read+0x67/0xe0
Mar 10 18:31:57 ubuntu kernel: [ 5430.721961]  __x64_sys_read+0x1a/0x20
Mar 10 18:31:57 ubuntu kernel: [ 5430.721966]  do_syscall_64+0x38/0x90
Mar 10 18:31:57 ubuntu kernel: [ 5430.721970]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
Mar 10 18:31:57 ubuntu kernel: [ 5430.721972] RIP: 0033:0x7f59cec88b32
Mar 10 18:31:57 ubuntu kernel: [ 5430.721975] Code: c0 e9 b2 fe ff ff 50 48 8d 3d 0a ab 0a 00 e8 65 08 02 00 0f 1f 44 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 0f 05 <48> 3d 00 f0 ff ff 77 56 c3 0f 1f 44 00 00 48 83 ec 28 48 89 54 24
Mar 10 18:31:57 ubuntu kernel: [ 5430.721976] RSP: 002b:00007ffced6960e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
Mar 10 18:31:57 ubuntu kernel: [ 5430.721978] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f59cec88b32
Mar 10 18:31:57 ubuntu kernel: [ 5430.721979] RDX: 0000000000020000 RSI: 00007f59cdd7b000 RDI: 0000000000000004
Mar 10 18:31:57 ubuntu kernel: [ 5430.721979] RBP: 00007f59cdd7b000 R08: 00007f59cdd7a010 R09: 00007f59cdd7a010
Mar 10 18:31:57 ubuntu kernel: [ 5430.721980] R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000000000
Mar 10 18:31:57 ubuntu kernel: [ 5430.721981] R13: 0000000000000004 R14: 0000000000020000 R15: 0000000000020000
Mar 10 18:31:57 ubuntu kernel: [ 5430.721983] Mem-Info:
Mar 10 18:31:57 ubuntu kernel: [ 5430.721987] active_anon:19913 inactive_anon:157458 isolated_anon:0
Mar 10 18:31:57 ubuntu kernel: [ 5430.721987]  active_file:287792 inactive_file:180605 isolated_file:25
Mar 10 18:31:57 ubuntu kernel: [ 5430.721987]  unevictable:8 dirty:10484 writeback:0
Mar 10 18:31:57 ubuntu kernel: [ 5430.721987]  slab_reclaimable:32064 slab_unreclaimable:13691
Mar 10 18:31:57 ubuntu kernel: [ 5430.721987]  mapped:40961 shmem:24905 pagetables:2966 bounce:0
Mar 10 18:31:57 ubuntu kernel: [ 5430.721987]  free:51892 free_pcp:30 free_cma:0
Mar 10 18:31:57 ubuntu kernel: [ 5430.721992] Node 0 active_anon:79652kB inactive_anon:629832kB active_file:1151168kB inactive_file:722420kB unevictable:32kB isolated(anon):0kB isolated(file):100kB mapped:163844kB dirty:41936kB writeback:0kB shmem:99620kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB kernel_stack:6576kB all_unreclaimable? no
Mar 10 18:31:57 ubuntu kernel: [ 5430.721993] Node 0 DMA free:11768kB min:240kB low:300kB high:360kB reserved_highatomic:0KB active_anon:0kB inactive_anon:220kB active_file:1708kB inactive_file:812kB unevictable:0kB writepending:80kB present:15996kB managed:15908kB mlocked:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
Mar 10 18:31:57 ubuntu kernel: [ 5430.721997] lowmem_reserve[]: 0 2860 2860 2860 2860
Mar 10 18:31:57 ubuntu kernel: [ 5430.722000] Node 0 DMA32 free:195800kB min:44812kB low:56012kB high:67212kB reserved_highatomic:0KB active_anon:79652kB inactive_anon:629612kB active_file:1149460kB inactive_file:722156kB unevictable:32kB writepending:41856kB present:3129280kB managed:3039300kB mlocked:32kB pagetables:11864kB bounce:0kB free_pcp:24kB local_pcp:20kB free_cma:0kB
Mar 10 18:31:57 ubuntu kernel: [ 5430.722003] lowmem_reserve[]: 0 0 0 0 0
Mar 10 18:31:57 ubuntu kernel: [ 5430.722007] Node 0 DMA: 4*4kB (E) 5*8kB (UE) 36*16kB (UME) 8*32kB (ME) 2*64kB (M) 2*128kB (UE) 1*256kB (U) 2*512kB (M) 3*1024kB (UME) 3*2048kB (UME) 0*4096kB = 11768kB
Mar 10 18:31:57 ubuntu kernel: [ 5430.722021] Node 0 DMA32: 8935*4kB (UME) 7419*8kB (UME) 3159*16kB (UME) 1013*32kB (UME) 219*64kB (UME) 35*128kB (UME) 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 196548kB
Mar 10 18:31:57 ubuntu kernel: [ 5430.722052] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
Mar 10 18:31:57 ubuntu kernel: [ 5430.722053] 493116 total pagecache pages
Mar 10 18:31:57 ubuntu kernel: [ 5430.722055] 38 pages in swap cache
Mar 10 18:31:57 ubuntu kernel: [ 5430.722056] Swap cache stats: add 11889, delete 11851, find 6/22
Mar 10 18:31:57 ubuntu kernel: [ 5430.722057] Free swap  = 338056kB
Mar 10 18:31:57 ubuntu kernel: [ 5430.722058] Total swap = 385928kB
Mar 10 18:31:57 ubuntu kernel: [ 5430.722059] 786319 pages RAM
Mar 10 18:31:57 ubuntu kernel: [ 5430.722060] 0 pages HighMem/MovableOnly
Mar 10 18:31:57 ubuntu kernel: [ 5430.722061] 22517 pages reserved
Mar 10 18:31:57 ubuntu kernel: [ 5430.722062] 0 pages hwpoisoned
Mar 10 18:31:57 ubuntu ubiquity: /proc/sys/kernel/printk
Mar 10 18:31:57 ubuntu ubiquity: : Cannot allocate memory