Hello, this crash happened twice when 5.14.21-150400.24.60 was booted and storing a ~35 MB mbox via NFS.I rebooted to 5.14.21-150400.24.55 and stored that file multiple times again with no problem: [ 2815.995840] BUG: kernel NULL pointer dereference, address: 0000000000000590 [ 2815.995865] #PF: supervisor write access in kernel mode [ 2815.995876] #PF: error_code(0x0002) - not-present page [ 2815.995886] PGD 0 P4D 0 [ 2815.995898] Oops: 0002 [#1] PREEMPT SMP NOPTI [ 2815.995912] CPU: 1 PID: 1654 Comm: nfsd Tainted: G N 5.14.21-150400.24.60-default #1 SLE15-SP4 9096397fa6646928cc6d185ba417f2af65b536f1 [ 2815.995932] Hardware name: Wortmann Terra 3100/Terra 3100, BIOS 080015 04/28/2011 [ 2815.995943] RIP: 0010:nfsd4_copy+0x14d/0x510 [nfsd] [ 2815.996045] Code: f0 01 00 00 e8 44 f9 26 e1 49 8b 85 70 0b 00 00 4e 8b 2c e0 e8 24 84 27 e1 bf f4 ff ff ff e8 ba 96 fe ff 48 8b 3d eb 0d 56 e2 <48> c7 04 25 90 05 00 00 90 05 00 00 ba 58 06 00 00 48 c7 04 25 98 [ 2815.996074] RSP: 0018:ffffa3c680c53dc0 EFLAGS: 00010246 [ 2815.996096] RAX: 0000000018270000 RBX: ffff93e6212fa2e0 RCX: ffffffffc0b22bc4 [ 2815.996117] RDX: 000000000000001a RSI: ffff93e6212300b4 RDI: ffff93e600042c00 [ 2815.996138] RBP: ffffa3c680c53df0 R08: 0000000000000000 R09: ffffa3c680c53cb0 [ 2815.996158] R10: 0000000000000000 R11: ffff93e60273eb40 R12: 000000000000000d [ 2815.996179] R13: ffff93e6105f6000 R14: ffff93e6212fa7bc R15: ffff93e6212fa848 [ 2815.996200] FS: 0000000000000000(0000) GS:ffff93e63bc80000(0000) knlGS:0000000000000000 [ 2815.996222] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2815.996242] CR2: 0000000000000590 CR3: 00000001042dc000 CR4: 00000000000006e0 [ 2815.996264] Call Trace: [ 2815.996286] <TASK> [ 2815.996314] ? nfsd4_proc_compound+0x4e4/0x6d0 [nfsd b83567b8ddafcaed6594f0c02db5f3f6ad3d7661] [ 2815.996419] nfsd4_proc_compound+0x4e4/0x6d0 [nfsd b83567b8ddafcaed6594f0c02db5f3f6ad3d7661] [ 2815.996519] nfsd_dispatch+0x1a9/0x270 [nfsd b83567b8ddafcaed6594f0c02db5f3f6ad3d7661] [ 2815.996611] svc_process_common+0x2be/0x760 [sunrpc ee66caa7b4260761f5723a182d4844fb5a86c8ec] [ 2815.996757] ? nfsd_svc+0x380/0x380 [nfsd b83567b8ddafcaed6594f0c02db5f3f6ad3d7661] [ 2815.996851] ? nfsd_shutdown_threads+0x90/0x90 [nfsd b83567b8ddafcaed6594f0c02db5f3f6ad3d7661] [ 2815.996942] svc_process+0xdb/0xf0 [sunrpc ee66caa7b4260761f5723a182d4844fb5a86c8ec] [ 2815.997081] nfsd+0xed/0x160 [nfsd b83567b8ddafcaed6594f0c02db5f3f6ad3d7661] [ 2815.997173] kthread+0x154/0x180 [ 2815.997199] ? set_kthread_struct+0x50/0x50 [ 2815.997224] ret_from_fork+0x1f/0x30 [ 2815.997252] </TASK> [ 2815.997269] Modules linked in: rpcsec_gss_krb5 ipt_REJECT af_packet 8021q garp mrp stp llc nft_objref nf_conntrack_netbios_ns nf_conntrack_broadcast nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_tables ebtable_nat ebtable_broute ip6table_nat ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c iptable_mangle iptable_raw iptable_security iscsi_ibft iscsi_boot_sysfs ip_set nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter bpfilter dmi_sysfs msr at24 regmap_i2c iTCO_wdt gpio_ich intel_pmc_bxt rtl8192ce(N) iTCO_vendor_support rtl_pci(N) rtl8192c_common(N) rtlwifi(N) mac80211 snd_hda_codec_idt snd_hda_codec_generic coretemp asus_wmi battery joydev libarc4 ledtrig_audio sparse_keymap snd_hda_codec_hdmi platform_profile pcspkr cfg80211 snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi i2c_i801 snd_hda_codec [ 2815.997449] lpc_ich mfd_core snd_hda_core snd_hwdep i2c_smbus snd_pcm jmb38x_ms snd_timer snd rfkill jme soundcore memstick mii thermal nfsd auth_rpcgss nfs_acl lockd grace sunrpc fuse configfs ip_tables x_tables ext4 crc16 mbcache jbd2 nouveau(N) hid_cherry hid_generic usbhid sr_mod drm_ttm_helper ttm cdrom sd_mod t10_pi i2c_algo_bit mxm_wmi(N) drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops cec rc_core uhci_hcd ahci ehci_pci drm sdhci_pci libahci ehci_hcd libata usbcore cqhci sdhci mmc_core serio_raw wmi video button sg dm_multipath dm_mod scsi_dh_rdac scsi_dh_emc scsi_dh_alua scsi_mod [ 2815.997769] Supported: No, Unsupported modules are loaded [ 2815.997789] CR2: 0000000000000590 [ 2815.997809] ---[ end trace fae5fa8282f7f82e ]--- [ 2815.997827] RIP: 0010:nfsd4_copy+0x14d/0x510 [nfsd] [ 2815.997925] Code: f0 01 00 00 e8 44 f9 26 e1 49 8b 85 70 0b 00 00 4e 8b 2c e0 e8 24 84 27 e1 bf f4 ff ff ff e8 ba 96 fe ff 48 8b 3d eb 0d 56 e2 <48> c7 04 25 90 05 00 00 90 05 00 00 ba 58 06 00 00 48 c7 04 25 98 [ 2815.997954] RSP: 0018:ffffa3c680c53dc0 EFLAGS: 00010246 [ 2815.997976] RAX: 0000000018270000 RBX: ffff93e6212fa2e0 RCX: ffffffffc0b22bc4 [ 2815.997996] RDX: 000000000000001a RSI: ffff93e6212300b4 RDI: ffff93e600042c00 [ 2815.998017] RBP: ffffa3c680c53df0 R08: 0000000000000000 R09: ffffa3c680c53cb0 [ 2815.998037] R10: 0000000000000000 R11: ffff93e60273eb40 R12: 000000000000000d [ 2815.998058] R13: ffff93e6105f6000 R14: ffff93e6212fa7bc R15: ffff93e6212fa848 [ 2815.998079] FS: 0000000000000000(0000) GS:ffff93e63bc80000(0000) knlGS:0000000000000000 [ 2815.998101] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2815.998121] CR2: 0000000000000590 CR3: 00000001042dc000 CR4: 00000000000006e0