[BUG] ARM64 regression: NULL pointer dereference in arm_smccc_version_init+0x90/0x1ac

[Emanuele Rocca]

On 2025-01-30 12:19, Mark Rutland wrote:
> For the benefit others, when we looked into this a few days ago it
> appeared that a GPR was being clobbered across an SMCCC call, resulting
> in a later crash (as that GPR should hold the ADRP'd base address of
> 'smccc_version'). I didn't have the time to dig more into that (e.g.  to
> figure out whether kernel/compiler/firmware was to blame).
> 
> Emanuele, could you please dump the result of:
> 
>   objdump --disassemble=arm_smccc_version_init vmlinux
> 
> ... for this kernel? That'd make it possible for others to
> perform/verify the analysis I mentioned above.

Sure, here it is:
https://people.debian.org/~ema/Z5OpGluX6oX5NLxh@NH27D9T0LF.objdump.txt

> If you can share any more details from the crash, that'd be helpful. The
> GPR dump would be *enormously* helpful in this case, and even a photo of
> the crash log might be useful.

pc : arm_smccc_version_init+0x90/0x1ac
lr : psci_probe+0x1fc/0x2c0
sp : ffffa3d8eea33ca0
x29: ffffa3d8eea33ce0 x28: 0000000081000200 x27: ffffa3d8edd72a80
x26: ffffa3d8edd728b0 x25: ffffa3d8eec66248 x24: ffffa3d8edc528d8
x23: ffffa3d8eed7f4f8 x22: 0000000000000001 x21: ffffa3d8eea58410
x20: ffffa3d8eed7f000 x19: 0000000000010001 x18: 0000000000000006
x17: 0000000009f69730 x16: 00000008760968d0 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
x11: 00000000ffffefff x10: ffffa3d8eeac09c8 x9 : ffffa3d8eea687d8
x8 : ffffa3d8eea33cb8 x7 : 0000000000000000 x6 : 0000000000000000 
x5 : ffffa3d8eed7f000 x4 : ffffa3d8edeb0000 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000000000001 x0 : 0000000000000000

Call trace:
 arm_smccc_version_init+0x90/0x1ac
 psci_0_2_init+0x20/0x2c
 psci_1_0_init+0x1c/0x58
 psci_dt_init+0x6c/0x98
 setup_arch+0x400/0x5ec
 start_kernel+0x90/0x788
 __primary_switched+0xbc/0xc4
Code: d29fffe1 eb01001f 1a9f97e0 f0ffd384 (b94264c2)

The above was transcribed by hand. I double-checked, but there may be
mistakes.

Photo here: https://people.debian.org/~ema/Z5OpGluX6oX5NLxh@NH27D9T0LF.jpg
 
Thanks,
  ema