Re: BUG: KASAN: vmalloc-out-of-bounds in copy_to_kernel_nofault+0xd8/0x1c8 (v6.13-rc6, PowerMac G4)

[Madhavan Srinivasan <maddy@linux.ibm.com>]

On 1/12/25 6:28 PM, Erhard Furtner wrote:
> Greetings!
> 
> I am getting this at bootup on my PowerMac G4 with a KASAN-enabled kernel 6.13-rc6:

Sorry for the delayed response,

Are you seeing this only in this kernel or this is the recent
kernel you tried to boot?

Maddy

> 
> [...]
> BUG: KASAN: vmalloc-out-of-bounds in copy_to_kernel_nofault+0xd8/0x1c8
> Write of size 8 at addr f1000000 by task chronyd/1293
> 
> CPU: 0 UID: 123 PID: 1293 Comm: chronyd Tainted: G        W          6.13.0-rc6-PMacG4 #2
> Tainted: [W]=WARN
> Hardware name: PowerMac3,6 7455 0x80010303 PowerMac
> Call Trace:
> [c2437590] [c1631a84] dump_stack_lvl+0x70/0x8c (unreliable)
> [c24375b0] [c0504998] print_report+0xdc/0x504
> [c2437610] [c050475c] kasan_report+0xf8/0x108
> [c2437690] [c0505a3c] kasan_check_range+0x24/0x18c
> [c24376a0] [c03fb5e4] copy_to_kernel_nofault+0xd8/0x1c8
> [c24376c0] [c004c014] patch_instructions+0x15c/0x16c
> [c2437710] [c00731a8] bpf_arch_text_copy+0x60/0x7c
> [c2437730] [c0281168] bpf_jit_binary_pack_finalize+0x50/0xac
> [c2437750] [c0073cf4] bpf_int_jit_compile+0xb30/0xdec
> [c2437880] [c0280394] bpf_prog_select_runtime+0x15c/0x478
> [c24378d0] [c1263428] bpf_prepare_filter+0xbf8/0xc14
> [c2437990] [c12677ec] bpf_prog_create_from_user+0x258/0x2b4
> [c24379d0] [c027111c] do_seccomp+0x3dc/0x1890
> [c2437ac0] [c001d8e0] system_call_exception+0x2dc/0x420
> [c2437f30] [c00281ac] ret_from_syscall+0x0/0x2c
> --- interrupt: c00 at 0x5a1274
> NIP:  005a1274 LR: 006a3b3c CTR: 005296c8
> REGS: c2437f40 TRAP: 0c00   Tainted: G        W           (6.13.0-rc6-PMacG4)
> MSR:  0200f932 <VEC,EE,PR,FP,ME,IR,DR,RI>  CR: 24004422  XER: 00000000
> 
> GPR00: 00000166 af8f3fa0 a7ee3540 00000001 00000000 013b6500 005a5858 0200f932 
> GPR08: 00000000 00001fe9 013d5fc8 005296c8 2822244c 00b2fcd8 00000000 af8f4b57 
> GPR16: 00000000 00000001 00000000 00000000 00000000 00000001 00000000 00000002 
> GPR24: 00afdbb0 00000000 00000000 00000000 006e0004 013ce060 006e7c1c 00000001 
> NIP [005a1274] 0x5a1274
> LR [006a3b3c] 0x6a3b3c
> --- interrupt: c00
> 
> The buggy address belongs to the virtual mapping at
>  [f1000000, f1002000) created by:
>  text_area_cpu_up+0x20/0x190
> 
> The buggy address belongs to the physical page:
> page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x76e30
> flags: 0x80000000(zone=2)
> raw: 80000000 00000000 00000122 00000000 00000000 00000000 ffffffff 00000001
> raw: 00000000
> page dumped because: kasan: bad access detected
> 
> Memory state around the buggy address:
>  f0ffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>  f0ffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> f1000000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>            ^
>  f1000080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>  f1000100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
> ==================================================================
> Disabling lock debugging due to kernel taint
> 
> 
> Kernel .config and full dmesg attached. The other 2 warnings in the dmesg, "workqueue: work disable count underflowed" are https://lore.kernel.org/all/CA+G9fYsQmFT3m1J0uGfWGJjci8MQoB7BNcmhBR175PAbxx9fBg@mail.gmail.com/ (offending commit should be reverted in next -rc) and "Missing '#size-cells'" is fixed by https://lore.kernel.org/all/87jzbqpnd9.fsf@mpe.ellerman.id.au/ (not yet merged)
> 
> Regards,
> Erhard