While booting linux-next (5.19.0-rc4-next-20220629) on Power8 non-virtualised following koject warning is seen: [ 0.000184] clocksource: timebase mult[1f40000] shift[24] registered [ 0.000303] clockevent: decrementer mult[83126e98] shift[32] cpu[0] [ 0.000397] ------------[ cut here ]------------ [ 0.000478] kobject: '(null)' ((____ptrval____)): is not initialized, yet kobject_get() is being called. [ 0.000667] WARNING: CPU: 0 PID: 0 at lib/kobject.c:626 kobject_get+0x90/0x100 [ 0.000802] Modules linked in: [ 0.000861] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.19.0-rc4-next-20220629 #1 [ 0.000995] NIP: c00000000073b0c0 LR: c00000000073b0bc CTR: c0000000000d33a0 [ 0.001120] REGS: c000000002a0f890 TRAP: 0700 Not tainted (5.19.0-rc4-next-20220629) [ 0.001260] MSR: 9000000002021033 <SF,HV,VEC,ME,IR,DR,RI,LE> CR: 28008822 XER: 20000000 [ 0.001428] CFAR: c00000000014f3a4 IRQMASK: 1 GPR00: c00000000073b0bc c000000002a0fb30 c000000002a12000 000000000000005c GPR04: 00000000ffff7fff c000000002a0f8f0 c000000002a0f8e8 0000000000000000 GPR08: c000000002826b78 0000000000000000 c000000002566a50 c0000000028e6bb8 GPR12: 0000000000008800 c000000002d00000 0000000000000003 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000278 c000000002a4dfe0 GPR20: c000000002a52238 c000000002a52820 c0000000000d8d60 c000000000fe6e18 GPR24: 0000000000000000 c000000002a0fe90 c000000000fe6e08 0000000000000000 GPR28: 0000000000000000 c000000002952e80 c000000ffffc3f10 c000000002952e80 [ 0.002681] NIP [c00000000073b0c0] kobject_get+0x90/0x100 [ 0.002781] LR [c00000000073b0bc] kobject_get+0x8c/0x100 [ 0.002880] Call Trace: [ 0.002925] [c000000002a0fb30] [c00000000073b0bc] kobject_get+0x8c/0x100 (unreliable) [ 0.003071] [c000000002a0fba0] [c00000000087e464] device_add+0xf4/0xb00 [ 0.003194] [c000000002a0fc80] [c000000000a7f6e4] of_device_add+0x64/0x80 [ 0.003321] [c000000002a0fcb0] [c000000000a800d0] of_platform_device_create_pdata+0xd0/0x1b0 [ 0.003476] [c000000002a0fd00] [c00000000201fa44] pnv_get_random_long_early+0x240/0x2e4 [ 0.003623] [c000000002a0fe20] [c000000002060c38] random_init+0xc0/0x214 [ 0.003749] [c000000002a0fec0] [c0000000020048bc] start_kernel+0x98c/0xbf4 [ 0.003878] [c000000002a0ff90] [c00000000000d978] start_here_common+0x1c/0x24 [ 0.004008] Instruction dump: [ 0.004063] 4e800020 60000000 60000000 60000000 7c0802a6 3c62fe65 7fe5fb78 3863a8e0 [ 0.004216] f8010080 e89f0000 4ba14285 60000000 <0fe00000> 60000000 60000000 60000000 [ 0.004372] ---[ end trace 0000000000000000 ]--- [ 0.004456] ------------[ cut here ]------------ [ 0.004537] refcount_t: addition on 0; use-after-free. [ 0.004645] WARNING: CPU: 0 PID: 0 at lib/refcount.c:25 refcount_warn_saturate+0x164/0x1f0 [ 0.004797] Modules linked in: [ 0.004853] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 5.19.0-rc4-next-20220629 #1 [ 0.005010] NIP: c0000000006e0a54 LR: c0000000006e0a50 CTR: c0000000000d33a0 [ 0.005134] REGS: c000000002a0f830 TRAP: 0700 Tainted: G W (5.19.0-rc4-next-20220629) Reverting the following patch helps avoid this warning. commit f3eac426657d985b97c92fa5f7ae1d43f04721f3 powerpc/powernv: wire up rng during setup_arch I have attached the dmesg log. Thanks - Sachin
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dmesg.log
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