When I use dd to create files multiple times under the ramfs file
system，Panic appears, indicating that there is no process to kill.
I learn that ramfs will automatically grow space due to data writing,
causing all the system memory to run out, but i think it shouldn't
cause the system to panic.
Is there any solution, or how to avoid this problem when using ramfs?
I use the qemu tool to reproduce this problem, The steps are as follows:
1. Use qemu to start the kernel using the ramfs file system
qemu-system-x86_64 -smp 2 -m 1024M -kernel bzImage -initrd
initramfs.cpio.gz -append "rdinit=/linuxrc console=ttyS0 loglevel=8
rootfstype=ramfs" -nographic
2.Check the file system type, as shown below
/ # stat -f .
File: "."
ID: 0 Namelen: 255 Type: romfs
Block size: 4096
Blocks: Total: 0 Free: 0 Available: 0
Inodes: Total: 0 Free: 0
3.Use dd multiple times to create large files, and the results
obtained are as follows:
===========================================================
/ # dd if=/dev/zero of=/bigfile bs=1M count=1024
[ 1647.230012] dd invoked oom-killer: gfp_mask=0x100cc2(GFP_HIGHUSER),
order=0, oom_score_adj=0
[ 1647.232632] CPU: 0 PID: 99 Comm: dd Not tainted 5.13.0-rc4-next-20210604+ #3
[ 1647.233060] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 1647.233060] Call Trace:
[ 1647.233060] dump_stack_lvl+0x58/0x71
[ 1647.233060] dump_header+0x4f/0x300
[ 1647.233060] oom_kill_process+0x2de/0x3a0
[ 1647.233060] ? find_lock_task_mm+0x3b/0x70
[ 1647.233060] out_of_memory+0xe9/0x6d0
[ 1647.233060] __alloc_pages_slowpath.constprop.134+0xa84/0xcb0
[ 1647.233060] __alloc_pages+0x2b9/0x2f0
[ 1647.233060] pagecache_get_page+0x164/0x3a0
[ 1647.233060] grab_cache_page_write_begin+0x17/0x30
[ 1647.233060] simple_write_begin+0x1e/0x1e0
[ 1647.233060] generic_perform_write+0xba/0x1c0
[ 1647.233060] __generic_file_write_iter+0x16b/0x1c0
[ 1647.233060] ? sysvec_apic_timer_interrupt+0x5b/0x80
[ 1647.233060] generic_file_write_iter+0x43/0xb0
[ 1647.233060] new_sync_write+0x10a/0x1a0
[ 1647.233060] vfs_write+0x153/0x230
[ 1647.233060] ksys_write+0x57/0xd0
[ 1647.233060] do_syscall_64+0x3a/0x90
[ 1647.233060] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 1647.233060] RIP: 0033:0x556cc0
[ 1647.233060] Code: 01 f0 ff ff 0f 83 60 df 01 00 c3 66 2e 0f 1f 84
00 00 00 00 00 0f 1f 44 00 00 83 3d c9 e5 32 00 00 75 14 b8 01 00 00
00 0f 05 <48> 3d 01 f0 ff ff 0f 83 34 df 01 00 c3 48 83 ec 08 e8 0a 82
00 00
[ 1647.233060] RSP: 002b:00007ffd22b93bf8 EFLAGS: 00000246 ORIG_RAX:
0000000000000001
[ 1647.233060] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000556cc0
[ 1647.233060] RDX: 0000000000100000 RSI: 00007f87a86a3010 RDI: 0000000000000001
[ 1647.233060] RBP: 00007f87a86a3010 R08: 0000000000000000 R09: 0000000000000000
[ 1647.233060] R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000100000
[ 1647.233060] R13: 0000000000000001 R14: 00007f87a86a3010 R15: 00007f87a86a3010
[ 1647.244474] Mem-Info:
[ 1647.244663] active_anon:3 inactive_anon:298 isolated_anon:0
[ 1647.244663] active_file:0 inactive_file:0 isolated_file:0
[ 1647.244663] unevictable:239648 dirty:0 writeback:0
[ 1647.244663] slab_reclaimable:2755 slab_unreclaimable:1689
[ 1647.244663] mapped:433 shmem:0 pagetables:27 bounce:0
[ 1647.244663] free:2908 free_pcp:241 free_cma:0
[ 1647.247244] Node 0 active_anon:12kB inactive_anon:1192kB
active_file:0kB inactive_file:0kB unevictable:958592kB
isolated(anon):0kB isolated(file):0kB mapped:1732kB dirty:0kB
writeback:0kB shmem:0kB writeback_tmp:0kB kernel_stack:768kB
pagetables:108kB all_unreclaimable? no
[ 1647.248762] Node 0 DMA free:3860kB min:60kB low:72kB high:84kB
reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
active_file:0kB inactive_file:0kB unevictable:11992kB writepending:0kB
present:15992kB managed:15908kB mlocked:0kB bounce:0kB free_pcp:12kB
local_pcp:4kB free_cma:0kB
[ 1647.250808] lowmem_reserve[]: 0 950 950 950
[ 1647.251262] Node 0 DMA32 free:7772kB min:8008kB low:8984kB
high:9960kB reserved_highatomic:0KB active_anon:12kB
inactive_anon:1192kB active_file:0kB inactive_file:0kB
unevictable:946620kB writepending:0kB present:1032064kB
managed:978680kB mlocked:0kB bounce:0kB free_pcp:952kB local_pcp:600kB
free_cma:0kB
[ 1647.253540] lowmem_reserve[]: 0 0 0 0
[ 1647.254260] Node 0 DMA: 1*4kB (U) 0*8kB 1*16kB (U) 2*32kB (UE)
1*64kB (E) 1*128kB (E) 2*256kB (UE) 2*512kB (UE) 2*1024kB (UE)
0*2048kB 0*4096kB = 3860kB
[ 1647.255533] Node 0 DMA32: 65*4kB (UME) 61*8kB (UME) 40*16kB (UME)
33*32kB (UME) 18*64kB (UME) 10*128kB (ME) 7*256kB (UM) 1*512kB (E)
1*1024kB (U) 0*2048kB 0*4096kB = 8204kB
[ 1647.267374] Node 0 hugepages_total=0 hugepages_free=0
hugepages_surp=0 hugepages_size=2048kB
[ 1647.271471] 239652 total pagecache pages
[ 1647.273281] 0 pages in swap cache
[ 1647.273709] Swap cache stats: add 0, delete 0, find 0/0
[ 1647.273991] Free swap = 0kB
[ 1647.276895] Total swap = 0kB
[ 1647.277779] 262014 pages RAM
[ 1647.277982] 0 pages HighMem/MovableOnly
[ 1647.278187] 13367 pages reserved
[ 1647.281882] Tasks state (memory values in pages):
[ 1647.281882] [ pid ] uid tgid total_vm rss pgtables_bytes
swapents oom_score_adj name
[ 1647.285417] [ 83] 0 83 720 455 36864
0 0 sh
[ 1647.285703] [ 99] 0 99 977 594 45056
0 0 dd
[ 1647.287121] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,task=dd,pid=99,uid=0
[ 1647.289756] Out of memory: Killed process 99 (dd) total-vm:3908kB,
anon-rss:964kB, file-rss:1412kB, shmem-rss:0kB, UID:0 pgtables:44kB
oom_score_adj:0
[ 1647.303507] dd (99) used greatest stack depth: 12872 bytes left
Killed
/ # dd if=/dev/zero of=/bigfile bs=1M count=1024
[ 1655.481958] dd invoked oom-killer: gfp_mask=0x100cc2(GFP_HIGHUSER),
order=0, oom_score_adj=0
[ 1655.486633] CPU: 1 PID: 100 Comm: dd Not tainted 5.13.0-rc4-next-20210604+ #3
[ 1655.487568] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 1655.487568] Call Trace:
[ 1655.487568] dump_stack_lvl+0x58/0x71
[ 1655.487568] dump_header+0x4f/0x300
[ 1655.487568] ? do_try_to_free_pages+0x214/0x310
[ 1655.487568] ? get_page_from_freelist+0x1d1/0xc40
[ 1655.487568] oom_kill_process+0x2de/0x3a0
[ 1655.487568] ? find_lock_task_mm+0x3b/0x70
[ 1655.487568] out_of_memory+0xe9/0x6d0
[ 1655.487568] __alloc_pages_slowpath.constprop.134+0xa84/0xcb0
[ 1655.487568] __alloc_pages+0x2b9/0x2f0
[ 1655.487568] pagecache_get_page+0x164/0x3a0
[ 1655.487568] grab_cache_page_write_begin+0x17/0x30
[ 1655.487568] simple_write_begin+0x1e/0x1e0
[ 1655.487568] generic_perform_write+0xba/0x1c0
[ 1655.487568] __generic_file_write_iter+0x16b/0x1c0
[ 1655.487568] ? sysvec_apic_timer_interrupt+0x5b/0x80
[ 1655.487568] generic_file_write_iter+0x43/0xb0
[ 1655.487568] new_sync_write+0x10a/0x1a0
[ 1655.487568] vfs_write+0x153/0x230
[ 1655.487568] ksys_write+0x57/0xd0
[ 1655.487568] do_syscall_64+0x3a/0x90
[ 1655.487568] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 1655.487568] RIP: 0033:0x556cc0
[ 1655.487568] Code: 01 f0 ff ff 0f 83 60 df 01 00 c3 66 2e 0f 1f 84
00 00 00 00 00 0f 1f 44 00 00 83 3d c9 e5 32 00 00 75 14 b8 01 00 00
00 0f 05 <48> 3d 01 f0 ff ff 0f 83 34 df 01 00 c3 48 83 ec 08 e8 0a 82
00 00
[ 1655.487568] RSP: 002b:00007fffafec7878 EFLAGS: 00000246 ORIG_RAX:
0000000000000001
[ 1655.487568] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000556cc0
[ 1655.487568] RDX: 0000000000100000 RSI: 00007f66bc740010 RDI: 0000000000000001
[ 1655.487568] RBP: 00007f66bc740010 R08: 0000000000000000 R09: 0000000000000000
[ 1655.487568] R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000100000
[ 1655.487568] R13: 0000000000000001 R14: 00007f66bc740010 R15: 00007f66bc740010
[ 1655.519386] Mem-Info:
[ 1655.519585] active_anon:3 inactive_anon:297 isolated_anon:0
[ 1655.519585] active_file:0 inactive_file:0 isolated_file:0
[ 1655.519585] unevictable:240802 dirty:0 writeback:0
[ 1655.519585] slab_reclaimable:2580 slab_unreclaimable:1655
[ 1655.519585] mapped:433 shmem:0 pagetables:28 bounce:0
[ 1655.519585] free:2033 free_pcp:414 free_cma:0
[ 1655.522018] Node 0 active_anon:12kB inactive_anon:1188kB
active_file:0kB inactive_file:0kB unevictable:963208kB
isolated(anon):0kB isolated(file):0kB mapped:1732kB dirty:0kB
writeback:0kB shmem:0kB writeback_tmp:0kB kernel_stack:768kB
pagetables:112kB all_unreclaimable? yes
[ 1655.522748] Node 0 DMA free:3860kB min:60kB low:72kB high:84kB
reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
active_file:0kB inactive_file:0kB unevictable:11968kB writepending:0kB
present:15992kB managed:15908kB mlocked:0kB bounce:0kB free_pcp:16kB
local_pcp:12kB free_cma:0kB
[ 1655.523733] lowmem_reserve[]: 0 950 950 950
[ 1655.524090] Node 0 DMA32 free:4272kB min:5960kB low:6936kB
high:7912kB reserved_highatomic:0KB active_anon:12kB
inactive_anon:1188kB active_file:0kB inactive_file:0kB
unevictable:951008kB writepending:0kB present:1032064kB
managed:978680kB mlocked:0kB bounce:0kB free_pcp:1640kB
local_pcp:952kB free_cma:0kB
[ 1655.525042] lowmem_reserve[]: 0 0 0 0
[ 1655.525200] Node 0 DMA: 1*4kB (U) 0*8kB 1*16kB (U) 0*32kB 2*64kB
(UE) 1*128kB (E) 2*256kB (UE) 2*512kB (UE) 2*1024kB (UE) 0*2048kB
0*4096kB = 3860kB
[ 1655.525702] Node 0 DMA32: 17*4kB (E) 2*8kB (UM) 2*16kB (UM) 2*32kB
(UM) 8*64kB (UME) 6*128kB (ME) 10*256kB (UME) 0*512kB 0*1024kB
0*2048kB 0*4096kB = 4020kB
[ 1655.526607] Node 0 hugepages_total=0 hugepages_free=0
hugepages_surp=0 hugepages_size=2048kB
[ 1655.527078] 240804 total pagecache pages
[ 1655.527219] 0 pages in swap cache
[ 1655.527326] Swap cache stats: add 0, delete 0, find 0/0
[ 1655.527472] Free swap = 0kB
[ 1655.527563] Total swap = 0kB
[ 1655.527657] 262014 pages RAM
[ 1655.527741] 0 pages HighMem/MovableOnly
[ 1655.528052] 13367 pages reserved
[ 1655.528168] Tasks state (memory values in pages):
[ 1655.528313] [ pid ] uid tgid total_vm rss pgtables_bytes
swapents oom_score_adj name
[ 1655.528564] [ 83] 0 83 720 455 36864
0 0 sh
[ 1655.529287] [ 100] 0 100 977 594 53248
0 0 dd
[ 1655.529565] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,task=dd,pid=100,uid=0
[ 1655.530157] Out of memory: Killed process 100 (dd) total-vm:3908kB,
anon-rss:964kB, file-rss:1412kB, shmem-rss:0kB, UID:0 pgtables:52kB
oom_score_adj:0
[ 1655.532126] oom_reaper: reaped process 100 (dd), now anon-rss:0kB,
file-rss:0kB, shmem-rss:0kB
Killed
/ # dd if=/dev/zero of=/bigfile bs=1M count=1024
[ 1656.785189] sh invoked oom-killer:
gfp_mask=0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_ZERO),
order=0, oom_score_adj=0
[ 1656.786309] CPU: 0 PID: 83 Comm: sh Not tainted 5.13.0-rc4-next-20210604+ #3
[ 1656.786655] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 1656.787037] Call Trace:
[ 1656.787177] dump_stack_lvl+0x58/0x71
[ 1656.787226] dump_header+0x4f/0x300
[ 1656.787226] ? do_try_to_free_pages+0x214/0x310
[ 1656.787226] ? get_page_from_freelist+0x1d1/0xc40
[ 1656.787226] oom_kill_process+0x2de/0x3a0
[ 1656.787226] ? find_lock_task_mm+0x3b/0x70
[ 1656.787226] out_of_memory+0xe9/0x6d0
[ 1656.787226] __alloc_pages_slowpath.constprop.134+0xa84/0xcb0
[ 1656.787226] __alloc_pages+0x2b9/0x2f0
[ 1656.787226] __alloc_pages_bulk+0x462/0x680
[ 1656.787226] ? __cond_resched+0x11/0x40
[ 1656.787226] ? __kmalloc_node+0x10d/0x270
[ 1656.787226] ? __vmalloc_node_range+0x211/0x300
[ 1656.787226] __vmalloc_node_range+0x122/0x300
[ 1656.787226] ? __cond_resched+0x11/0x40
[ 1656.787226] copy_process+0x780/0x1950
[ 1656.787226] ? kernel_clone+0x96/0x3e0
[ 1656.787226] ? __cond_resched+0x11/0x40
[ 1656.787226] ? down_read+0x9/0xa0
[ 1656.787226] ? _copy_to_user+0x1c/0x30
[ 1656.787226] kernel_clone+0x96/0x3e0
[ 1656.787226] ? tty_ioctl+0x148/0x890
[ 1656.787226] __do_sys_clone+0x5e/0x80
[ 1656.787226] do_syscall_64+0x3a/0x90
[ 1656.787226] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 1656.787226] RIP: 0033:0x534a4a
[ 1656.787226] Code: f7 d8 64 89 04 25 d4 02 00 00 64 4c 8b 0c 25 10
00 00 00 31 d2 4d 8d 91 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00
00 0f 05 <48> 3d 00 f0 ff ff 0f 87 f5 00 00 00 85 c0 41 89 c5 0f 85 fc
00 00
[ 1656.787226] RSP: 002b:00007ffe6e976910 EFLAGS: 00000246 ORIG_RAX:
0000000000000038
[ 1656.787226] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000534a4a
[ 1656.787226] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
[ 1656.787226] RBP: 00007ffe6e976930 R08: 0000000000000000 R09: 000000000128f880
[ 1656.787226] R10: 000000000128fb50 R11: 0000000000000246 R12: 0000000000000053
[ 1656.787226] R13: 0000000001290c98 R14: 0000000000000000 R15: 0000000000000000
[ 1656.794113] Mem-Info:
[ 1656.794222] active_anon:2 inactive_anon:29 isolated_anon:0
[ 1656.794222] active_file:0 inactive_file:0 isolated_file:0
[ 1656.794222] unevictable:240817 dirty:0 writeback:0
[ 1656.794222] slab_reclaimable:2588 slab_unreclaimable:1655
[ 1656.794222] mapped:433 shmem:0 pagetables:18 bounce:0
[ 1656.794222] free:1970 free_pcp:699 free_cma:0
[ 1656.795238] Node 0 active_anon:8kB inactive_anon:116kB
active_file:0kB inactive_file:0kB unevictable:963268kB
isolated(anon):0kB isolated(file):0kB mapped:1732kB dirty:0kB
writeback:0kB shmem:0kB writeback_tmp:0kB kernel_stack:752kB
pagetables:72kB all_unreclaimable? yes
[ 1656.796010] Node 0 DMA free:3860kB min:60kB low:72kB high:84kB
reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
active_file:0kB inactive_file:0kB unevictable:11968kB writepending:0kB
present:15992kB managed:15908kB mlocked:0kB bounce:0kB free_pcp:16kB
local_pcp:4kB free_cma:0kB
[ 1656.797721] lowmem_reserve[]: 0 950 950 950
[ 1656.797967] Node 0 DMA32 free:4020kB min:5960kB low:6936kB
high:7912kB reserved_highatomic:0KB active_anon:8kB
inactive_anon:116kB active_file:0kB inactive_file:0kB
unevictable:951300kB writepending:0kB present:1032064kB
managed:978680kB mlocked:0kB bounce:0kB free_pcp:2780kB
local_pcp:688kB free_cma:0kB
[ 1656.798578] lowmem_reserve[]: 0 0 0 0
[ 1656.798775] Node 0 DMA: 1*4kB (U) 0*8kB 1*16kB (U) 0*32kB 2*64kB
(UE) 1*128kB (E) 2*256kB (UE) 2*512kB (UE) 2*1024kB (UE) 0*2048kB
0*4096kB = 3860kB
[ 1656.801548] Node 0 DMA32: 17*4kB (E) 2*8kB (UM) 2*16kB (UM) 2*32kB
(UM) 8*64kB (UME) 6*128kB (ME) 10*256kB (UME) 0*512kB 0*1024kB
0*2048kB 0*4096kB = 4020kB
[ 1656.802683] Node 0 hugepages_total=0 hugepages_free=0
hugepages_surp=0 hugepages_size=2048kB
[ 1656.803319] 240817 total pagecache pages
[ 1656.803534] 0 pages in swap cache
[ 1656.803717] Swap cache stats: add 0, delete 0, find 0/0
[ 1656.804122] Free swap = 0kB
[ 1656.804286] Total swap = 0kB
[ 1656.804426] 262014 pages RAM
[ 1656.804565] 0 pages HighMem/MovableOnly
[ 1656.804748] 13367 pages reserved
[ 1656.805060] Tasks state (memory values in pages):
[ 1656.805374] [ pid ] uid tgid total_vm rss pgtables_bytes
swapents oom_score_adj name
[ 1656.806160] [ 83] 0 83 720 455 36864
0 0 sh
[ 1656.806677] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,task=sh,pid=83,uid=0
[ 1656.807762] Out of memory: Killed process 83 (sh) total-vm:2880kB,
anon-rss:88kB, file-rss:1732kB, shmem-rss:0kB, UID:0 pgtables:36kB
oom_score_adj:0
[ 1656.824587] linuxrc invoked oom-killer:
gfp_mask=0x400dc0(GFP_KERNEL_ACCOUNT|__GFP_ZERO), order=1,
oom_score_adj=0
[ 1656.825261] CPU: 1 PID: 1 Comm: linuxrc Not tainted
5.13.0-rc4-next-20210604+ #3
[ 1656.825508] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 1656.825784] Call Trace:
[ 1656.826015] dump_stack_lvl+0x58/0x71
[ 1656.826086] dump_header+0x4f/0x300
[ 1656.826086] out_of_memory+0x67c/0x6d0
[ 1656.826086] __alloc_pages_slowpath.constprop.134+0xa84/0xcb0
[ 1656.826086] __alloc_pages+0x2b9/0x2f0
[ 1656.826086] __get_free_pages+0x8/0x30
[ 1656.826086] pgd_alloc+0x2a/0x1c0
[ 1656.826086] ? kmem_cache_alloc+0x31/0x1c0
[ 1656.826086] mm_init.isra.61+0x172/0x240
[ 1656.826086] dup_mm.isra.63+0x54/0x540
[ 1656.826086] copy_process+0x18b6/0x1950
[ 1656.826086] kernel_clone+0x96/0x3e0
[ 1656.826086] __do_sys_clone+0x5e/0x80
[ 1656.826086] do_syscall_64+0x3a/0x90
[ 1656.826086] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 1656.826086] RIP: 0033:0x534a4a
[ 1656.826086] Code: f7 d8 64 89 04 25 d4 02 00 00 64 4c 8b 0c 25 10
00 00 00 31 d2 4d 8d 91 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00
00 0f 05 <48> 3d 00 f0 ff ff 0f 87 f5 00 00 00 85 c0 41 89 c5 0f 85 fc
00 00
[ 1656.826086] RSP: 002b:00007ffea9111680 EFLAGS: 00000246 ORIG_RAX:
0000000000000038
[ 1656.826086] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000534a4a
[ 1656.826086] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
[ 1656.826086] RBP: 00007ffea91116a0 R08: 0000000000000000 R09: 0000000000e71880
[ 1656.826086] R10: 0000000000e71b50 R11: 0000000000000246 R12: 0000000000000001
[ 1656.826086] R13: 00007ffea91119c8 R14: 0000000000000000 R15: 0000000000000095
[ 1656.831099] Mem-Info:
[ 1656.831211] active_anon:2 inactive_anon:29 isolated_anon:0
[ 1656.831211] active_file:0 inactive_file:0 isolated_file:0
[ 1656.831211] unevictable:240817 dirty:0 writeback:0
[ 1656.831211] slab_reclaimable:2588 slab_unreclaimable:1655
[ 1656.831211] mapped:382 shmem:0 pagetables:18 bounce:0
[ 1656.831211] free:1970 free_pcp:728 free_cma:0
[ 1656.832252] Node 0 active_anon:8kB inactive_anon:116kB
active_file:0kB inactive_file:0kB unevictable:963268kB
isolated(anon):0kB isolated(file):0kB mapped:1528kB dirty:0kB
writeback:0kB shmem:0kB writeback_tmp:0kB kernel_stack:752kB
pagetables:72kB all_unreclaimable? yes
[ 1656.833095] Node 0 DMA free:3860kB min:60kB low:72kB high:84kB
reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
active_file:0kB inactive_file:0kB unevictable:11968kB writepending:0kB
present:15992kB managed:15908kB mlocked:0kB bounce:0kB free_pcp:16kB
local_pcp:12kB free_cma:0kB
[ 1656.834023] lowmem_reserve[]: 0 950 950 950
[ 1656.834191] Node 0 DMA32 free:4020kB min:5960kB low:6936kB
high:7912kB reserved_highatomic:0KB active_anon:8kB
inactive_anon:116kB active_file:0kB inactive_file:0kB
unevictable:951300kB writepending:0kB present:1032064kB
managed:978680kB mlocked:0kB bounce:0kB free_pcp:2896kB
local_pcp:2100kB free_cma:0kB
[ 1656.835186] lowmem_reserve[]: 0 0 0 0
[ 1656.835344] Node 0 DMA: 1*4kB (U) 0*8kB 1*16kB (U) 0*32kB 2*64kB
(UE) 1*128kB (E) 2*256kB (UE) 2*512kB (UE) 2*1024kB (UE) 0*2048kB
0*4096kB = 3860kB
[ 1656.835831] Node 0 DMA32: 17*4kB (E) 2*8kB (UM) 2*16kB (UM) 2*32kB
(UM) 8*64kB (UME) 6*128kB (ME) 10*256kB (UME) 0*512kB 0*1024kB
0*2048kB 0*4096kB = 4020kB
[ 1656.836493] Node 0 hugepages_total=0 hugepages_free=0
hugepages_surp=0 hugepages_size=2048kB
[ 1656.836734] 240817 total pagecache pages
[ 1656.837020] 0 pages in swap cache
[ 1656.837119] Swap cache stats: add 0, delete 0, find 0/0
[ 1656.837268] Free swap = 0kB
[ 1656.837359] Total swap = 0kB
[ 1656.837452] 262014 pages RAM
[ 1656.837533] 0 pages HighMem/MovableOnly
[ 1656.837648] 13367 pages reserved
[ 1656.837747] Tasks state (memory values in pages):
[ 1656.838049] [ pid ] uid tgid total_vm rss pgtables_bytes
swapents oom_score_adj name
[ 1656.838340] Out of memory and no killable processes...
[ 1656.838682] Kernel panic - not syncing: System is deadlocked on memory
[ 1656.838990] CPU: 1 PID: 1 Comm: linuxrc Not tainted
5.13.0-rc4-next-20210604+ #3
[ 1656.838990] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 1656.838990] Call Trace:
[ 1656.838990] dump_stack_lvl+0x58/0x71
[ 1656.838990] panic+0xf3/0x2b4
[ 1656.838990] out_of_memory+0x6c1/0x6d0
[ 1656.838990] __alloc_pages_slowpath.constprop.134+0xa84/0xcb0
[ 1656.838990] __alloc_pages+0x2b9/0x2f0
[ 1656.838990] __get_free_pages+0x8/0x30
[ 1656.838990] pgd_alloc+0x2a/0x1c0
[ 1656.838990] ? kmem_cache_alloc+0x31/0x1c0
[ 1656.838990] mm_init.isra.61+0x172/0x240
[ 1656.838990] dup_mm.isra.63+0x54/0x540
[ 1656.838990] copy_process+0x18b6/0x1950
[ 1656.838990] kernel_clone+0x96/0x3e0
[ 1656.838990] __do_sys_clone+0x5e/0x80
[ 1656.838990] do_syscall_64+0x3a/0x90
[ 1656.838990] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 1656.838990] RIP: 0033:0x534a4a
[ 1656.838990] Code: f7 d8 64 89 04 25 d4 02 00 00 64 4c 8b 0c 25 10
00 00 00 31 d2 4d 8d 91 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00
00 0f 05 <48> 3d 00 f0 ff ff 0f 87 f5 00 00 00 85 c0 41 89 c5 0f 85 fc
00 00
[ 1656.838990] RSP: 002b:00007ffea9111680 EFLAGS: 00000246 ORIG_RAX:
0000000000000038
[ 1656.838990] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000534a4a
[ 1656.838990] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
[ 1656.838990] RBP: 00007ffea91116a0 R08: 0000000000000000 R09: 0000000000e71880
[ 1656.838990] R10: 0000000000e71b50 R11: 0000000000000246 R12: 0000000000000001
[ 1656.838990] R13: 00007ffea91119c8 R14: 0000000000000000 R15: 0000000000000095
[ 1656.838990] Kernel Offset: 0x31600000 from 0xffffffff81000000
(relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 1656.838990] ---[ end Kernel panic - not syncing: System is
deadlocked on memory ]---
===========================================================
Hello, is there any solution, or how to avoid this problem when using ramfs?
yong w <[email protected]> 于2021年7月7日周三 下午5:58写道：
>
> When I use dd to create files multiple times under the ramfs file
> system，Panic appears, indicating that there is no process to kill.
> I learn that ramfs will automatically grow space due to data writing,
> causing all the system memory to run out, but i think it shouldn't
> cause the system to panic.
> Is there any solution, or how to avoid this problem when using ramfs?
>
> I use the qemu tool to reproduce this problem, The steps are as follows:
> 1. Use qemu to start the kernel using the ramfs file system
> qemu-system-x86_64 -smp 2 -m 1024M -kernel bzImage -initrd
> initramfs.cpio.gz -append "rdinit=/linuxrc console=ttyS0 loglevel=8
> rootfstype=ramfs" -nographic
> 2.Check the file system type, as shown below
> / # stat -f .
> File: "."
> ID: 0 Namelen: 255 Type: romfs
> Block size: 4096
> Blocks: Total: 0 Free: 0 Available: 0
> Inodes: Total: 0 Free: 0
> 3.Use dd multiple times to create large files, and the results
> obtained are as follows:
> ===========================================================
> / # dd if=/dev/zero of=/bigfile bs=1M count=1024
> [ 1647.230012] dd invoked oom-killer: gfp_mask=0x100cc2(GFP_HIGHUSER),
> order=0, oom_score_adj=0
> [ 1647.232632] CPU: 0 PID: 99 Comm: dd Not tainted 5.13.0-rc4-next-20210604+ #3
> [ 1647.233060] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
> [ 1647.233060] Call Trace:
> [ 1647.233060] dump_stack_lvl+0x58/0x71
> [ 1647.233060] dump_header+0x4f/0x300
> [ 1647.233060] oom_kill_process+0x2de/0x3a0
> [ 1647.233060] ? find_lock_task_mm+0x3b/0x70
> [ 1647.233060] out_of_memory+0xe9/0x6d0
> [ 1647.233060] __alloc_pages_slowpath.constprop.134+0xa84/0xcb0
> [ 1647.233060] __alloc_pages+0x2b9/0x2f0
> [ 1647.233060] pagecache_get_page+0x164/0x3a0
> [ 1647.233060] grab_cache_page_write_begin+0x17/0x30
> [ 1647.233060] simple_write_begin+0x1e/0x1e0
> [ 1647.233060] generic_perform_write+0xba/0x1c0
> [ 1647.233060] __generic_file_write_iter+0x16b/0x1c0
> [ 1647.233060] ? sysvec_apic_timer_interrupt+0x5b/0x80
> [ 1647.233060] generic_file_write_iter+0x43/0xb0
> [ 1647.233060] new_sync_write+0x10a/0x1a0
> [ 1647.233060] vfs_write+0x153/0x230
> [ 1647.233060] ksys_write+0x57/0xd0
> [ 1647.233060] do_syscall_64+0x3a/0x90
> [ 1647.233060] entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 1647.233060] RIP: 0033:0x556cc0
> [ 1647.233060] Code: 01 f0 ff ff 0f 83 60 df 01 00 c3 66 2e 0f 1f 84
> 00 00 00 00 00 0f 1f 44 00 00 83 3d c9 e5 32 00 00 75 14 b8 01 00 00
> 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 34 df 01 00 c3 48 83 ec 08 e8 0a 82
> 00 00
> [ 1647.233060] RSP: 002b:00007ffd22b93bf8 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000001
> [ 1647.233060] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000556cc0
> [ 1647.233060] RDX: 0000000000100000 RSI: 00007f87a86a3010 RDI: 0000000000000001
> [ 1647.233060] RBP: 00007f87a86a3010 R08: 0000000000000000 R09: 0000000000000000
> [ 1647.233060] R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000100000
> [ 1647.233060] R13: 0000000000000001 R14: 00007f87a86a3010 R15: 00007f87a86a3010
> [ 1647.244474] Mem-Info:
> [ 1647.244663] active_anon:3 inactive_anon:298 isolated_anon:0
> [ 1647.244663] active_file:0 inactive_file:0 isolated_file:0
> [ 1647.244663] unevictable:239648 dirty:0 writeback:0
> [ 1647.244663] slab_reclaimable:2755 slab_unreclaimable:1689
> [ 1647.244663] mapped:433 shmem:0 pagetables:27 bounce:0
> [ 1647.244663] free:2908 free_pcp:241 free_cma:0
> [ 1647.247244] Node 0 active_anon:12kB inactive_anon:1192kB
> active_file:0kB inactive_file:0kB unevictable:958592kB
> isolated(anon):0kB isolated(file):0kB mapped:1732kB dirty:0kB
> writeback:0kB shmem:0kB writeback_tmp:0kB kernel_stack:768kB
> pagetables:108kB all_unreclaimable? no
> [ 1647.248762] Node 0 DMA free:3860kB min:60kB low:72kB high:84kB
> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> active_file:0kB inactive_file:0kB unevictable:11992kB writepending:0kB
> present:15992kB managed:15908kB mlocked:0kB bounce:0kB free_pcp:12kB
> local_pcp:4kB free_cma:0kB
> [ 1647.250808] lowmem_reserve[]: 0 950 950 950
> [ 1647.251262] Node 0 DMA32 free:7772kB min:8008kB low:8984kB
> high:9960kB reserved_highatomic:0KB active_anon:12kB
> inactive_anon:1192kB active_file:0kB inactive_file:0kB
> unevictable:946620kB writepending:0kB present:1032064kB
> managed:978680kB mlocked:0kB bounce:0kB free_pcp:952kB local_pcp:600kB
> free_cma:0kB
> [ 1647.253540] lowmem_reserve[]: 0 0 0 0
> [ 1647.254260] Node 0 DMA: 1*4kB (U) 0*8kB 1*16kB (U) 2*32kB (UE)
> 1*64kB (E) 1*128kB (E) 2*256kB (UE) 2*512kB (UE) 2*1024kB (UE)
> 0*2048kB 0*4096kB = 3860kB
> [ 1647.255533] Node 0 DMA32: 65*4kB (UME) 61*8kB (UME) 40*16kB (UME)
> 33*32kB (UME) 18*64kB (UME) 10*128kB (ME) 7*256kB (UM) 1*512kB (E)
> 1*1024kB (U) 0*2048kB 0*4096kB = 8204kB
> [ 1647.267374] Node 0 hugepages_total=0 hugepages_free=0
> hugepages_surp=0 hugepages_size=2048kB
> [ 1647.271471] 239652 total pagecache pages
> [ 1647.273281] 0 pages in swap cache
> [ 1647.273709] Swap cache stats: add 0, delete 0, find 0/0
> [ 1647.273991] Free swap = 0kB
> [ 1647.276895] Total swap = 0kB
> [ 1647.277779] 262014 pages RAM
> [ 1647.277982] 0 pages HighMem/MovableOnly
> [ 1647.278187] 13367 pages reserved
> [ 1647.281882] Tasks state (memory values in pages):
> [ 1647.281882] [ pid ] uid tgid total_vm rss pgtables_bytes
> swapents oom_score_adj name
> [ 1647.285417] [ 83] 0 83 720 455 36864
> 0 0 sh
> [ 1647.285703] [ 99] 0 99 977 594 45056
> 0 0 dd
> [ 1647.287121] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,task=dd,pid=99,uid=0
> [ 1647.289756] Out of memory: Killed process 99 (dd) total-vm:3908kB,
> anon-rss:964kB, file-rss:1412kB, shmem-rss:0kB, UID:0 pgtables:44kB
> oom_score_adj:0
> [ 1647.303507] dd (99) used greatest stack depth: 12872 bytes left
> Killed
> / # dd if=/dev/zero of=/bigfile bs=1M count=1024
> [ 1655.481958] dd invoked oom-killer: gfp_mask=0x100cc2(GFP_HIGHUSER),
> order=0, oom_score_adj=0
> [ 1655.486633] CPU: 1 PID: 100 Comm: dd Not tainted 5.13.0-rc4-next-20210604+ #3
> [ 1655.487568] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
> [ 1655.487568] Call Trace:
> [ 1655.487568] dump_stack_lvl+0x58/0x71
> [ 1655.487568] dump_header+0x4f/0x300
> [ 1655.487568] ? do_try_to_free_pages+0x214/0x310
> [ 1655.487568] ? get_page_from_freelist+0x1d1/0xc40
> [ 1655.487568] oom_kill_process+0x2de/0x3a0
> [ 1655.487568] ? find_lock_task_mm+0x3b/0x70
> [ 1655.487568] out_of_memory+0xe9/0x6d0
> [ 1655.487568] __alloc_pages_slowpath.constprop.134+0xa84/0xcb0
> [ 1655.487568] __alloc_pages+0x2b9/0x2f0
> [ 1655.487568] pagecache_get_page+0x164/0x3a0
> [ 1655.487568] grab_cache_page_write_begin+0x17/0x30
> [ 1655.487568] simple_write_begin+0x1e/0x1e0
> [ 1655.487568] generic_perform_write+0xba/0x1c0
> [ 1655.487568] __generic_file_write_iter+0x16b/0x1c0
> [ 1655.487568] ? sysvec_apic_timer_interrupt+0x5b/0x80
> [ 1655.487568] generic_file_write_iter+0x43/0xb0
> [ 1655.487568] new_sync_write+0x10a/0x1a0
> [ 1655.487568] vfs_write+0x153/0x230
> [ 1655.487568] ksys_write+0x57/0xd0
> [ 1655.487568] do_syscall_64+0x3a/0x90
> [ 1655.487568] entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 1655.487568] RIP: 0033:0x556cc0
> [ 1655.487568] Code: 01 f0 ff ff 0f 83 60 df 01 00 c3 66 2e 0f 1f 84
> 00 00 00 00 00 0f 1f 44 00 00 83 3d c9 e5 32 00 00 75 14 b8 01 00 00
> 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 34 df 01 00 c3 48 83 ec 08 e8 0a 82
> 00 00
> [ 1655.487568] RSP: 002b:00007fffafec7878 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000001
> [ 1655.487568] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000556cc0
> [ 1655.487568] RDX: 0000000000100000 RSI: 00007f66bc740010 RDI: 0000000000000001
> [ 1655.487568] RBP: 00007f66bc740010 R08: 0000000000000000 R09: 0000000000000000
> [ 1655.487568] R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000100000
> [ 1655.487568] R13: 0000000000000001 R14: 00007f66bc740010 R15: 00007f66bc740010
> [ 1655.519386] Mem-Info:
> [ 1655.519585] active_anon:3 inactive_anon:297 isolated_anon:0
> [ 1655.519585] active_file:0 inactive_file:0 isolated_file:0
> [ 1655.519585] unevictable:240802 dirty:0 writeback:0
> [ 1655.519585] slab_reclaimable:2580 slab_unreclaimable:1655
> [ 1655.519585] mapped:433 shmem:0 pagetables:28 bounce:0
> [ 1655.519585] free:2033 free_pcp:414 free_cma:0
> [ 1655.522018] Node 0 active_anon:12kB inactive_anon:1188kB
> active_file:0kB inactive_file:0kB unevictable:963208kB
> isolated(anon):0kB isolated(file):0kB mapped:1732kB dirty:0kB
> writeback:0kB shmem:0kB writeback_tmp:0kB kernel_stack:768kB
> pagetables:112kB all_unreclaimable? yes
> [ 1655.522748] Node 0 DMA free:3860kB min:60kB low:72kB high:84kB
> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> active_file:0kB inactive_file:0kB unevictable:11968kB writepending:0kB
> present:15992kB managed:15908kB mlocked:0kB bounce:0kB free_pcp:16kB
> local_pcp:12kB free_cma:0kB
> [ 1655.523733] lowmem_reserve[]: 0 950 950 950
> [ 1655.524090] Node 0 DMA32 free:4272kB min:5960kB low:6936kB
> high:7912kB reserved_highatomic:0KB active_anon:12kB
> inactive_anon:1188kB active_file:0kB inactive_file:0kB
> unevictable:951008kB writepending:0kB present:1032064kB
> managed:978680kB mlocked:0kB bounce:0kB free_pcp:1640kB
> local_pcp:952kB free_cma:0kB
> [ 1655.525042] lowmem_reserve[]: 0 0 0 0
> [ 1655.525200] Node 0 DMA: 1*4kB (U) 0*8kB 1*16kB (U) 0*32kB 2*64kB
> (UE) 1*128kB (E) 2*256kB (UE) 2*512kB (UE) 2*1024kB (UE) 0*2048kB
> 0*4096kB = 3860kB
> [ 1655.525702] Node 0 DMA32: 17*4kB (E) 2*8kB (UM) 2*16kB (UM) 2*32kB
> (UM) 8*64kB (UME) 6*128kB (ME) 10*256kB (UME) 0*512kB 0*1024kB
> 0*2048kB 0*4096kB = 4020kB
> [ 1655.526607] Node 0 hugepages_total=0 hugepages_free=0
> hugepages_surp=0 hugepages_size=2048kB
> [ 1655.527078] 240804 total pagecache pages
> [ 1655.527219] 0 pages in swap cache
> [ 1655.527326] Swap cache stats: add 0, delete 0, find 0/0
> [ 1655.527472] Free swap = 0kB
> [ 1655.527563] Total swap = 0kB
> [ 1655.527657] 262014 pages RAM
> [ 1655.527741] 0 pages HighMem/MovableOnly
> [ 1655.528052] 13367 pages reserved
> [ 1655.528168] Tasks state (memory values in pages):
> [ 1655.528313] [ pid ] uid tgid total_vm rss pgtables_bytes
> swapents oom_score_adj name
> [ 1655.528564] [ 83] 0 83 720 455 36864
> 0 0 sh
> [ 1655.529287] [ 100] 0 100 977 594 53248
> 0 0 dd
> [ 1655.529565] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,task=dd,pid=100,uid=0
> [ 1655.530157] Out of memory: Killed process 100 (dd) total-vm:3908kB,
> anon-rss:964kB, file-rss:1412kB, shmem-rss:0kB, UID:0 pgtables:52kB
> oom_score_adj:0
> [ 1655.532126] oom_reaper: reaped process 100 (dd), now anon-rss:0kB,
> file-rss:0kB, shmem-rss:0kB
> Killed
> / # dd if=/dev/zero of=/bigfile bs=1M count=1024
> [ 1656.785189] sh invoked oom-killer:
> gfp_mask=0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_ZERO),
> order=0, oom_score_adj=0
> [ 1656.786309] CPU: 0 PID: 83 Comm: sh Not tainted 5.13.0-rc4-next-20210604+ #3
> [ 1656.786655] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
> [ 1656.787037] Call Trace:
> [ 1656.787177] dump_stack_lvl+0x58/0x71
> [ 1656.787226] dump_header+0x4f/0x300
> [ 1656.787226] ? do_try_to_free_pages+0x214/0x310
> [ 1656.787226] ? get_page_from_freelist+0x1d1/0xc40
> [ 1656.787226] oom_kill_process+0x2de/0x3a0
> [ 1656.787226] ? find_lock_task_mm+0x3b/0x70
> [ 1656.787226] out_of_memory+0xe9/0x6d0
> [ 1656.787226] __alloc_pages_slowpath.constprop.134+0xa84/0xcb0
> [ 1656.787226] __alloc_pages+0x2b9/0x2f0
> [ 1656.787226] __alloc_pages_bulk+0x462/0x680
> [ 1656.787226] ? __cond_resched+0x11/0x40
> [ 1656.787226] ? __kmalloc_node+0x10d/0x270
> [ 1656.787226] ? __vmalloc_node_range+0x211/0x300
> [ 1656.787226] __vmalloc_node_range+0x122/0x300
> [ 1656.787226] ? __cond_resched+0x11/0x40
> [ 1656.787226] copy_process+0x780/0x1950
> [ 1656.787226] ? kernel_clone+0x96/0x3e0
> [ 1656.787226] ? __cond_resched+0x11/0x40
> [ 1656.787226] ? down_read+0x9/0xa0
> [ 1656.787226] ? _copy_to_user+0x1c/0x30
> [ 1656.787226] kernel_clone+0x96/0x3e0
> [ 1656.787226] ? tty_ioctl+0x148/0x890
> [ 1656.787226] __do_sys_clone+0x5e/0x80
> [ 1656.787226] do_syscall_64+0x3a/0x90
> [ 1656.787226] entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 1656.787226] RIP: 0033:0x534a4a
> [ 1656.787226] Code: f7 d8 64 89 04 25 d4 02 00 00 64 4c 8b 0c 25 10
> 00 00 00 31 d2 4d 8d 91 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00
> 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 f5 00 00 00 85 c0 41 89 c5 0f 85 fc
> 00 00
> [ 1656.787226] RSP: 002b:00007ffe6e976910 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000038
> [ 1656.787226] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000534a4a
> [ 1656.787226] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
> [ 1656.787226] RBP: 00007ffe6e976930 R08: 0000000000000000 R09: 000000000128f880
> [ 1656.787226] R10: 000000000128fb50 R11: 0000000000000246 R12: 0000000000000053
> [ 1656.787226] R13: 0000000001290c98 R14: 0000000000000000 R15: 0000000000000000
> [ 1656.794113] Mem-Info:
> [ 1656.794222] active_anon:2 inactive_anon:29 isolated_anon:0
> [ 1656.794222] active_file:0 inactive_file:0 isolated_file:0
> [ 1656.794222] unevictable:240817 dirty:0 writeback:0
> [ 1656.794222] slab_reclaimable:2588 slab_unreclaimable:1655
> [ 1656.794222] mapped:433 shmem:0 pagetables:18 bounce:0
> [ 1656.794222] free:1970 free_pcp:699 free_cma:0
> [ 1656.795238] Node 0 active_anon:8kB inactive_anon:116kB
> active_file:0kB inactive_file:0kB unevictable:963268kB
> isolated(anon):0kB isolated(file):0kB mapped:1732kB dirty:0kB
> writeback:0kB shmem:0kB writeback_tmp:0kB kernel_stack:752kB
> pagetables:72kB all_unreclaimable? yes
> [ 1656.796010] Node 0 DMA free:3860kB min:60kB low:72kB high:84kB
> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> active_file:0kB inactive_file:0kB unevictable:11968kB writepending:0kB
> present:15992kB managed:15908kB mlocked:0kB bounce:0kB free_pcp:16kB
> local_pcp:4kB free_cma:0kB
> [ 1656.797721] lowmem_reserve[]: 0 950 950 950
> [ 1656.797967] Node 0 DMA32 free:4020kB min:5960kB low:6936kB
> high:7912kB reserved_highatomic:0KB active_anon:8kB
> inactive_anon:116kB active_file:0kB inactive_file:0kB
> unevictable:951300kB writepending:0kB present:1032064kB
> managed:978680kB mlocked:0kB bounce:0kB free_pcp:2780kB
> local_pcp:688kB free_cma:0kB
> [ 1656.798578] lowmem_reserve[]: 0 0 0 0
> [ 1656.798775] Node 0 DMA: 1*4kB (U) 0*8kB 1*16kB (U) 0*32kB 2*64kB
> (UE) 1*128kB (E) 2*256kB (UE) 2*512kB (UE) 2*1024kB (UE) 0*2048kB
> 0*4096kB = 3860kB
> [ 1656.801548] Node 0 DMA32: 17*4kB (E) 2*8kB (UM) 2*16kB (UM) 2*32kB
> (UM) 8*64kB (UME) 6*128kB (ME) 10*256kB (UME) 0*512kB 0*1024kB
> 0*2048kB 0*4096kB = 4020kB
> [ 1656.802683] Node 0 hugepages_total=0 hugepages_free=0
> hugepages_surp=0 hugepages_size=2048kB
> [ 1656.803319] 240817 total pagecache pages
> [ 1656.803534] 0 pages in swap cache
> [ 1656.803717] Swap cache stats: add 0, delete 0, find 0/0
> [ 1656.804122] Free swap = 0kB
> [ 1656.804286] Total swap = 0kB
> [ 1656.804426] 262014 pages RAM
> [ 1656.804565] 0 pages HighMem/MovableOnly
> [ 1656.804748] 13367 pages reserved
> [ 1656.805060] Tasks state (memory values in pages):
> [ 1656.805374] [ pid ] uid tgid total_vm rss pgtables_bytes
> swapents oom_score_adj name
> [ 1656.806160] [ 83] 0 83 720 455 36864
> 0 0 sh
> [ 1656.806677] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,task=sh,pid=83,uid=0
> [ 1656.807762] Out of memory: Killed process 83 (sh) total-vm:2880kB,
> anon-rss:88kB, file-rss:1732kB, shmem-rss:0kB, UID:0 pgtables:36kB
> oom_score_adj:0
> [ 1656.824587] linuxrc invoked oom-killer:
> gfp_mask=0x400dc0(GFP_KERNEL_ACCOUNT|__GFP_ZERO), order=1,
> oom_score_adj=0
> [ 1656.825261] CPU: 1 PID: 1 Comm: linuxrc Not tainted
> 5.13.0-rc4-next-20210604+ #3
> [ 1656.825508] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
> [ 1656.825784] Call Trace:
> [ 1656.826015] dump_stack_lvl+0x58/0x71
> [ 1656.826086] dump_header+0x4f/0x300
> [ 1656.826086] out_of_memory+0x67c/0x6d0
> [ 1656.826086] __alloc_pages_slowpath.constprop.134+0xa84/0xcb0
> [ 1656.826086] __alloc_pages+0x2b9/0x2f0
> [ 1656.826086] __get_free_pages+0x8/0x30
> [ 1656.826086] pgd_alloc+0x2a/0x1c0
> [ 1656.826086] ? kmem_cache_alloc+0x31/0x1c0
> [ 1656.826086] mm_init.isra.61+0x172/0x240
> [ 1656.826086] dup_mm.isra.63+0x54/0x540
> [ 1656.826086] copy_process+0x18b6/0x1950
> [ 1656.826086] kernel_clone+0x96/0x3e0
> [ 1656.826086] __do_sys_clone+0x5e/0x80
> [ 1656.826086] do_syscall_64+0x3a/0x90
> [ 1656.826086] entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 1656.826086] RIP: 0033:0x534a4a
> [ 1656.826086] Code: f7 d8 64 89 04 25 d4 02 00 00 64 4c 8b 0c 25 10
> 00 00 00 31 d2 4d 8d 91 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00
> 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 f5 00 00 00 85 c0 41 89 c5 0f 85 fc
> 00 00
> [ 1656.826086] RSP: 002b:00007ffea9111680 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000038
> [ 1656.826086] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000534a4a
> [ 1656.826086] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
> [ 1656.826086] RBP: 00007ffea91116a0 R08: 0000000000000000 R09: 0000000000e71880
> [ 1656.826086] R10: 0000000000e71b50 R11: 0000000000000246 R12: 0000000000000001
> [ 1656.826086] R13: 00007ffea91119c8 R14: 0000000000000000 R15: 0000000000000095
> [ 1656.831099] Mem-Info:
> [ 1656.831211] active_anon:2 inactive_anon:29 isolated_anon:0
> [ 1656.831211] active_file:0 inactive_file:0 isolated_file:0
> [ 1656.831211] unevictable:240817 dirty:0 writeback:0
> [ 1656.831211] slab_reclaimable:2588 slab_unreclaimable:1655
> [ 1656.831211] mapped:382 shmem:0 pagetables:18 bounce:0
> [ 1656.831211] free:1970 free_pcp:728 free_cma:0
> [ 1656.832252] Node 0 active_anon:8kB inactive_anon:116kB
> active_file:0kB inactive_file:0kB unevictable:963268kB
> isolated(anon):0kB isolated(file):0kB mapped:1528kB dirty:0kB
> writeback:0kB shmem:0kB writeback_tmp:0kB kernel_stack:752kB
> pagetables:72kB all_unreclaimable? yes
> [ 1656.833095] Node 0 DMA free:3860kB min:60kB low:72kB high:84kB
> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> active_file:0kB inactive_file:0kB unevictable:11968kB writepending:0kB
> present:15992kB managed:15908kB mlocked:0kB bounce:0kB free_pcp:16kB
> local_pcp:12kB free_cma:0kB
> [ 1656.834023] lowmem_reserve[]: 0 950 950 950
> [ 1656.834191] Node 0 DMA32 free:4020kB min:5960kB low:6936kB
> high:7912kB reserved_highatomic:0KB active_anon:8kB
> inactive_anon:116kB active_file:0kB inactive_file:0kB
> unevictable:951300kB writepending:0kB present:1032064kB
> managed:978680kB mlocked:0kB bounce:0kB free_pcp:2896kB
> local_pcp:2100kB free_cma:0kB
> [ 1656.835186] lowmem_reserve[]: 0 0 0 0
> [ 1656.835344] Node 0 DMA: 1*4kB (U) 0*8kB 1*16kB (U) 0*32kB 2*64kB
> (UE) 1*128kB (E) 2*256kB (UE) 2*512kB (UE) 2*1024kB (UE) 0*2048kB
> 0*4096kB = 3860kB
> [ 1656.835831] Node 0 DMA32: 17*4kB (E) 2*8kB (UM) 2*16kB (UM) 2*32kB
> (UM) 8*64kB (UME) 6*128kB (ME) 10*256kB (UME) 0*512kB 0*1024kB
> 0*2048kB 0*4096kB = 4020kB
> [ 1656.836493] Node 0 hugepages_total=0 hugepages_free=0
> hugepages_surp=0 hugepages_size=2048kB
> [ 1656.836734] 240817 total pagecache pages
> [ 1656.837020] 0 pages in swap cache
> [ 1656.837119] Swap cache stats: add 0, delete 0, find 0/0
> [ 1656.837268] Free swap = 0kB
> [ 1656.837359] Total swap = 0kB
> [ 1656.837452] 262014 pages RAM
> [ 1656.837533] 0 pages HighMem/MovableOnly
> [ 1656.837648] 13367 pages reserved
> [ 1656.837747] Tasks state (memory values in pages):
> [ 1656.838049] [ pid ] uid tgid total_vm rss pgtables_bytes
> swapents oom_score_adj name
> [ 1656.838340] Out of memory and no killable processes...
> [ 1656.838682] Kernel panic - not syncing: System is deadlocked on memory
> [ 1656.838990] CPU: 1 PID: 1 Comm: linuxrc Not tainted
> 5.13.0-rc4-next-20210604+ #3
> [ 1656.838990] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
> [ 1656.838990] Call Trace:
> [ 1656.838990] dump_stack_lvl+0x58/0x71
> [ 1656.838990] panic+0xf3/0x2b4
> [ 1656.838990] out_of_memory+0x6c1/0x6d0
> [ 1656.838990] __alloc_pages_slowpath.constprop.134+0xa84/0xcb0
> [ 1656.838990] __alloc_pages+0x2b9/0x2f0
> [ 1656.838990] __get_free_pages+0x8/0x30
> [ 1656.838990] pgd_alloc+0x2a/0x1c0
> [ 1656.838990] ? kmem_cache_alloc+0x31/0x1c0
> [ 1656.838990] mm_init.isra.61+0x172/0x240
> [ 1656.838990] dup_mm.isra.63+0x54/0x540
> [ 1656.838990] copy_process+0x18b6/0x1950
> [ 1656.838990] kernel_clone+0x96/0x3e0
> [ 1656.838990] __do_sys_clone+0x5e/0x80
> [ 1656.838990] do_syscall_64+0x3a/0x90
> [ 1656.838990] entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 1656.838990] RIP: 0033:0x534a4a
> [ 1656.838990] Code: f7 d8 64 89 04 25 d4 02 00 00 64 4c 8b 0c 25 10
> 00 00 00 31 d2 4d 8d 91 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00
> 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 f5 00 00 00 85 c0 41 89 c5 0f 85 fc
> 00 00
> [ 1656.838990] RSP: 002b:00007ffea9111680 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000038
> [ 1656.838990] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000534a4a
> [ 1656.838990] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
> [ 1656.838990] RBP: 00007ffea91116a0 R08: 0000000000000000 R09: 0000000000e71880
> [ 1656.838990] R10: 0000000000e71b50 R11: 0000000000000246 R12: 0000000000000001
> [ 1656.838990] R13: 00007ffea91119c8 R14: 0000000000000000 R15: 0000000000000095
> [ 1656.838990] Kernel Offset: 0x31600000 from 0xffffffff81000000
> (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
> [ 1656.838990] ---[ end Kernel panic - not syncing: System is
> deadlocked on memory ]---
> ===========================================================
> -----Original Messages-----
> From: "yong w" <[email protected]>
> Sent Time: 2021-07-14 08:24:23 (Wednesday)
> To: [email protected], [email protected], [email protected], [email protected], [email protected]
> Cc:
> Subject: Re: [BUG] ramfs system panic when using dd to create files
>
> Hello, is there any solution, or how to avoid this problem when using ramfs?
Limit max size of ramfs.
>
> yong w <[email protected]> 于2021年7月7日周三 下午5:58写道：
> >
> > When I use dd to create files multiple times under the ramfs file
> > system，Panic appears, indicating that there is no process to kill.
> > I learn that ramfs will automatically grow space due to data writing,
> > causing all the system memory to run out, but i think it shouldn't
> > cause the system to panic.
The comments already explains why kernel should panic on this situation:
/*
* If we got here due to an actual allocation at the
* system level, we cannot survive this and will enter
* an endless loop in the allocator. Bail out now.
*/
</[email protected]></[email protected]>
Thanks for your reply!
> Limit max size of ramfs.
It's no use using size to limit the size of ramfs.
"mount -t ramfs -o size=10M ramfs /ramfs" is the command i use.
>
> The comments already explains why kernel should panic on this situation:
> /*
> * If we got here due to an actual allocation at the
> * system level, we cannot survive this and will enter
> * an endless loop in the allocator. Bail out now.
> */
But it causes panic, actually , I don't want it panics
On Wed 14-07-21 15:35:36, wuzhouhui wrote:
> > -----Original Messages-----
> > From: "yong w" <[email protected]>
> > Sent Time: 2021-07-14 08:24:23 (Wednesday)
> > To: [email protected], [email protected], [email protected], [email protected], [email protected]
> > Cc:
> > Subject: Re: [BUG] ramfs system panic when using dd to create files
> >
> > Hello, is there any solution, or how to avoid this problem when using ramfs?
>
> Limit max size of ramfs.
>
> >
> > yong w <[email protected]> 于2021年7月7日周三 下午5:58写道：
> > >
> > > When I use dd to create files multiple times under the ramfs file
> > > system，Panic appears, indicating that there is no process to kill.
> > > I learn that ramfs will automatically grow space due to data writing,
> > > causing all the system memory to run out, but i think it shouldn't
> > > cause the system to panic.
>
> The comments already explains why kernel should panic on this situation:
> /*
> * If we got here due to an actual allocation at the
> * system level, we cannot survive this and will enter
> * an endless loop in the allocator. Bail out now.
> */
That is the oom side of the things. And that is way too late to do
anything more reasonable. It is suspicious that the ramfs can consume
arbitrary amount of memory. I would be looking there.
--
Michal Hocko
SUSE Labs
On Wed, Jul 14, 2021 at 10:30:22PM +0800, yong w wrote:
> Thanks for your reply!
>
> > Limit max size of ramfs.
> It's no use using size to limit the size of ramfs.
> "mount -t ramfs -o size=10M ramfs /ramfs" is the command i use.
>
ramfs does not support size= limiting, that's what tmpfs is for.
> >
> > The comments already explains why kernel should panic on this situation:
> > /*
> > * If we got here due to an actual allocation at the
> > * system level, we cannot survive this and will enter
> > * an endless loop in the allocator. Bail out now.
> > */
>
> But it causes panic, actually , I don't want it panics
Then use tmpfs and specify size=. It's mentioned in filesystems/tmpfs.rst
--8<--
If you compare it to ramfs (which was the template to create tmpfs)
you gain swapping and limit checking. Another similar thing is the RAM
disk (/dev/ram*), which simulates a fixed size hard disk in physical
RAM, where you have to create an ordinary filesystem on top. Ramdisks
cannot swap and you do not have the possibility to resize them.
--8<--
--
Mel Gorman
SUSE Labs