Re: [PATCH v3] ARM: imx: Fix suspend/resume crash with Clang CFI

[Sami Tolvanen]

On Wed, Jul 22, 2026 at 5:54 AM Yo'av Moshe <linux@xxxxxxxxxxxxx> wrote:
>
> On 2026-07-21 8:09 PM, Nathan Chancellor wrote:
> > Does using SYM_TYPED_FUNC_START for imx6_suspend() make that work?
> > Something like this builds fine for me and I see
> > __kcfi_typeid_imx6_suspend generated by Clang.
> Hi Nathan,
>
> Thanks for the suggestion!
>
> Unfortunately my physical board died, so I couldn't test this on hardware.
> However, I gave your patch a try under QEMU emulation (with CONFIG_CFI=y
> and copying the 4-byte hash into OCRAM before fncpy), and it still
> triggered a CFI panic when suspending:
>
>     __und_svc_finish from imx6q_suspend_finish+0x78/0xd0
>
> It seems like the hash generated for assembly doesn't match what the C code
> expects at the call site.

Are relocations applied to this code before the function is copied?
Because SYM_TYPED_FUNC_START doesn't embed the actual CFI hash in the
binary, just a reference to a symbol that contains the hash, and it
relies on the kernel to apply relocations before indirect calls are
made to the function.

Sami