nsfd goes BOOOM with allocation failure in |nfsd_shutdown_threads()| ...

[Roland Mainz]

Hi!

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Is this a known bug - nfsd goes "boooom" in a regular basis, once or
twice a week (kernel is stock Debian Linux "5.10.0-22-rt-amd64", NFSv4
client is both Debian Linux NFSv4 /home on the same machine and
Windows NFSv4 client (git
https://github.com/kofemann/ms-nfs41-client/commit/0be33d4eceeb7be668d6252f06c79394100e98e0)
compiling Cygwin gcc in two instances in a Win10 VMware VM):
---- snip ----
Dec 21 03:47:22 derfwpc5131 kernel: nfsd: page allocation failure:
order:4, mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO),
nodemask=(null),cpuset=/,mems_allowed=0
Dec 21 03:47:22 derfwpc5131 kernel: CPU: 4 PID: 938 Comm: nfsd
Tainted: G           OE     5.10.0-22-rt-amd64 #1 Debian 5.10.178-3
Dec 21 03:47:22 derfwpc5131 kernel: Hardware name: FUJITSU ESPRIMO
P500/D2991-A1, BIOS V4.6.4.0 R1.9.0 for D2991-A1x 11/22/2011
Dec 21 03:47:22 derfwpc5131 kernel: Call Trace:
Dec 21 03:47:22 derfwpc5131 kernel:  dump_stack+0x6b/0x83
Dec 21 03:47:22 derfwpc5131 kernel:  warn_alloc+0x138/0x160
Dec 21 03:47:22 derfwpc5131 kernel:  ? __alloc_pages_direct_compact+0x13c/0x160
Dec 21 03:47:22 derfwpc5131 kernel:
__alloc_pages_slowpath.constprop.0+0xd2a/0xd60
Dec 21 03:47:22 derfwpc5131 kernel:  __alloc_pages_nodemask+0x330/0x360
Dec 21 03:47:22 derfwpc5131 kernel:  kmalloc_order+0x28/0x100
Dec 21 03:47:22 derfwpc5131 kernel:  kmalloc_order_trace+0x19/0xc0
Dec 21 03:47:22 derfwpc5131 kernel:
nfs4svc_decode_compoundargs+0x1c4/0x4e0 [nfsd]
Dec 21 03:47:22 derfwpc5131 kernel:  nfsd_dispatch+0x74/0x190 [nfsd]
Dec 21 03:47:22 derfwpc5131 kernel:  svc_process_common+0x4c4/0x760 [sunrpc]
Dec 21 03:47:22 derfwpc5131 kernel:  ? nfsd_svc+0x330/0x330 [nfsd]
Dec 21 03:47:22 derfwpc5131 kernel:  ? nfsd_shutdown_threads+0x90/0x90 [nfsd]
Dec 21 03:47:22 derfwpc5131 kernel:  svc_process+0xb7/0xf0 [sunrpc]
Dec 21 03:47:22 derfwpc5131 kernel:  nfsd+0xed/0x150 [nfsd]
Dec 21 03:47:22 derfwpc5131 kernel:  kthread+0x184/0x1a0
Dec 21 03:47:22 derfwpc5131 kernel:  ? __kthread_parkme+0xa0/0xa0
Dec 21 03:47:22 derfwpc5131 kernel:  ret_from_fork+0x1f/0x30
Dec 21 03:47:22 derfwpc5131 kernel: Mem-Info:
Dec 21 03:47:22 derfwpc5131 kernel: active_anon:877124
inactive_anon:1712597 isolated_anon:0
                                     active_file:2886463
inactive_file:2349094 isolated_file:0
                                     unevictable:5345 dirty:41979 writeback:0
                                     slab_reclaimable:129086
slab_unreclaimable:62421
                                     mapped:2173650 shmem:2222800
pagetables:11932 bounce:0
                                     free:78612 free_pcp:165 free_cma:0
Dec 21 03:47:22 derfwpc5131 kernel: Node 0 active_anon:3508496kB
inactive_anon:6850388kB active_file:11545852kB inactive_file:9396376kB
unevictable:21380kB isolated(anon):0kB isolated(file):0kB
mapped:8694600kB dirty:167916kB writeback:0kB shmem:8891200kB
writeback_tmp:0kB kernel_stack:14240kB all_unreclaimable? no
Dec 21 03:47:22 derfwpc5131 kernel: Node 0 DMA free:11264kB min:8kB
low:20kB high:32kB reserved_highatomic:0KB active_anon:0kB
inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB
writepending:0kB present:15984kB managed:15360kB mlocked:0kB
pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
Dec 21 03:47:22 derfwpc5131 kernel: lowmem_reserve[]: 0 2850 31933 31933 31933
Dec 21 03:47:22 derfwpc5131 kernel: Node 0 DMA32 free:118320kB
min:2040kB low:4956kB high:7872kB reserved_highatomic:0KB
active_anon:54420kB inactive_anon:128020kB active_file:848044kB
inactive_file:1680696kB unevictable:0kB writepending:224kB
present:3033892kB managed:2968356kB mlocked:0kB pagetables:108kB
bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
Dec 21 03:47:22 derfwpc5131 kernel: lowmem_reserve[]: 0 0 29083 29083 29083
Dec 21 03:47:22 derfwpc5131 kernel: Node 0 Normal free:184864kB
min:20824kB low:50604kB high:80384kB reserved_highatomic:2048KB
active_anon:3454076kB inactive_anon:6722368kB active_file:10697808kB
inactive_file:7715632kB unevictable:21380kB writepending:167692kB
present:30406656kB managed:29788648kB mlocked:64kB pagetables:47620kB
bounce:0kB free_pcp:664kB local_pcp:344kB free_cma:0kB
Dec 21 03:47:22 derfwpc5131 kernel: lowmem_reserve[]: 0 0 0 0 0
Dec 21 03:47:22 derfwpc5131 kernel: Node 0 DMA: 0*4kB 0*8kB 0*16kB
0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 1*1024kB (U) 1*2048kB (M)
2*4096kB (M) = 11264kB
Dec 21 03:47:22 derfwpc5131 kernel: Node 0 DMA32: 2816*4kB (UME)
1184*8kB (UME) 135*16kB (UME) 197*32kB (UME) 24*64kB (UME) 403*128kB
(UM) 139*256kB (M) 4*512kB (UM) 0*1024kB 0*2048kB 0*4096kB = 119952kB
Dec 21 03:47:22 derfwpc5131 kernel: Node 0 Normal: 20111*4kB (UME)
7934*8kB (UME) 2449*16kB (UMEH) 78*32kB (UEH) 7*64kB (H) 5*128kB (H)
2*256kB (H) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 187196kB
Dec 21 03:47:22 derfwpc5131 kernel: Node 0 hugepages_total=0
hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
Dec 21 03:47:22 derfwpc5131 kernel: 7487517 total pagecache pages
Dec 21 03:47:22 derfwpc5131 kernel: 29084 pages in swap cache
Dec 21 03:47:22 derfwpc5131 kernel: Swap cache stats: add 510992,
delete 481907, find 455115/506520
Dec 21 03:47:22 derfwpc5131 kernel: Free swap  = 32781168kB
Dec 21 03:47:22 derfwpc5131 kernel: Total swap = 33554428kB
Dec 21 03:47:22 derfwpc5131 kernel: 8364133 pages RAM
Dec 21 03:47:22 derfwpc5131 kernel: 0 pages HighMem/MovableOnly
Dec 21 03:47:22 derfwpc5131 kernel: 171042 pages reserved
Dec 21 03:47:22 derfwpc5131 kernel: 0 pages hwpoisoned
---- snip ----

The Win10 NFSv4 client at that point lost the NFSv4 session,
recovered, and the gcc build continued without problems.

Is the |nfsd_shutdown_threads()| in the stacktrace "normal", or is
nfsd really shutting down at this moment ?

----

Bye,
Roland
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