Re: [BUG] tpm_tis_plat_probe -- maps a borrowed MEM resource by its own size, then reads at a FIXED 0xF00 offset

[Jarkko Sakkinen]

On Thu, Aug 27, 2026 at 10:37:00PM -0700, Farhad Alemi wrote:
> Hello,
> 
> As part of the kernel research at ASU's SEFCOM
> lab, we hit the crash below. Crash reports can be found here:
> 
>   https://github.com/farhad-alemi/public_bug_reports/tree/main/154-tpm_tis-borrowed-resource-fixed-offset-read/

Please describe instead in plain Enligsh what is going. Hopping into 
random Github links is not the best possible way to communicate.

> 
>   BUG: unable to handle page fault for address: ffffc90000a17310
>   #PF: supervisor read access in kernel mode
>   #PF: error_code(0x0000) - not-present page
>   Oops: Oops: 0000 [#1] SMP KASAN NOPTI
>   RIP: 0010:ioread32+0x1c/0x80
>   Call Trace:
>    ioread32+0x1c/0x80
>    tpm_tcg_read_bytes+0xec/0x270
>    tpm_tis_core_init+0x48c/0x1830
>    tpm_tis_init+0x420/0x540
>    tpm_tis_plat_probe+0x118/0x1a0
>    platform_probe+0xf9/0x190
>    really_probe+0x267/0xaf0
>    device_driver_attach+0xe0/0x1d0
>    bind_store+0x1d0/0x220
>    kernfs_fop_write_iter+0x3af/0x540
>    ksys_write+0x150/0x270
>   Kernel panic - not syncing: Fatal exception
> 
> Our reproducer.c is available upon request.
> 
> Happy to test a patch if that would help.
> 
> Regards,

BR, Jarkko