powernv_rng_read: Oops: Kernel access of bad area, sig: 11 [#1]

[    0.000000] Linux version 7.1.0-rc2+ 
(pmenzel@flughafenberlinbrandenburgwillybrandt.molgen.mpg.de) (gcc 
(Ubuntu 11.2.0-7ubuntu2) 11.2.0, GNU ld (GNU Binutils for Ubuntu) 2.37) 
#3 SMP PREEMPT Wed May  6 08:50:58 CEST 2026
[…]
[   17.901992] Kernel attempted to read user page (0) - exploit attempt? 
(uid: 0)
[   17.902011] BUG: Kernel NULL pointer dereference on read at 0x00000000
[   17.902018] Faulting instruction address: 0xc0000000000e7138
[   17.902027] Oops: Kernel access of bad area, sig: 11 [#1]
[   17.902034] LE PAGE_SIZE=64K MMU=Hash  SMP NR_CPUS=2048 NUMA PowerNV
[   17.902045] Modules linked in: powernv_rng(+) bnx2x ofpart ibmpowernv 
bfq mdio cmdlinepart powernv_flash ipmi_powernv ipmi_devintf mtd 
ipmi_msghandler at24(+) vmx_crypto opal_prd sch_fq_codel nfsd parport_pc 
ppdev auth_rpcgss nfs_acl lp lockd grace parport sunrpc autofs4 btrfs 
xor libblake2b raid6_pq ast drm_shmem_helper drm_client_lib i2c_algo_bit 
drm_kms_helper drm ahci drm_panel_orientation_quirks libahci
[   17.902185] CPU: 147 UID: 0 PID: 2626 Comm: hwrng Not tainted 
7.1.0-rc2+ #3 PREEMPTLAZY
[   17.902197] Hardware name: 8335-GCA POWER8 (raw) 0x4d0200 
opal:skiboot-5.4.8-5787ad3 PowerNV
[   17.902204] NIP:  c0000000000e7138 LR: c00800001ec8013c CTR: 
c0000000000e70fc
[   17.902212] REGS: c000000092913c50 TRAP: 0300   Not tainted  (7.1.0-rc2+)
[   17.902222] MSR:  900000000280b033 
<SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 44420220  XER: 20000000
[   17.902269] CFAR: c00800001ec8026c DAR: 0000000000000000 DSISR: 
40000000 IRQMASK: 0
                GPR00: c00800001ec8013c c000000092913ef0 
c000000001c18100 c00000002222d900
                GPR04: c00000002222d900 0000000000000080 
0000000000000001 0000000000000000
                GPR08: 0000000000000000 c000000002212000 
c0000000951e1780 c00800001ec80258
                GPR12: c0000000000e70fc c00000ffff6fd700 
c0000000001d11c0 c00000001b99b9c0
                GPR16: 0000000000000000 0000000000000000 
0000000000000000 0000000000000000
                GPR20: 0000000000000000 0000000000000000 
0000000000000000 0000000000000000
                GPR24: 0000000000000000 c000000002fe6a58 
0000000000000000 0000000000000000
                GPR28: c000000002fe6a20 0000000000000010 
000000000000000f c00000002222d900
[   17.902406] NIP [c0000000000e7138] pnv_get_random_long+0x3c/0x114
[   17.902426] LR [c00800001ec8013c] powernv_rng_read+0x78/0xc4 
[powernv_rng]
[   17.902444] Call Trace:
[   17.902448] [c000000092913ef0] [c000000092913f30] 0xc000000092913f30 
(unreliable)
[   17.902463] [c000000092913f30] [c000000000decd58] hwrng_fillfn+0xd4/0x3dc
[   17.902484] [c000000092913f90] [c0000000001d1328] kthread+0x170/0x1a4
[   17.902498] [c000000092913fe0] [c00000000000d030] 
start_kernel_thread+0x14/0x18
[   17.902513] Code: 60000000 7d2000a6 71290010 418200bc e94d0908 
812a0000 39290001 912a0000 e90d0030 3d220060 39299f00 7d08482a 
<e9280000> 7c0004ac e8e90000 0c070000
[   17.902569] ---[ end trace 0000000000000000 ]---
[   18.008801] pstore: backend (nvram) writing error (-1)

[   18.015458] note: hwrng[2626] exited with irqs disabled
[   18.015483] note: hwrng[2626] exited with preempt_count 1