[PATCH] arm64/efi: Avoid voluntary preemption with efi_mm installed

[Will Deacon]

On Tue, 11 Aug 2026 15:04:29 +0100, Will Deacon wrote:
> Gus reports a bad kernel memory access when using software PAN
> (CONFIG_ARM64_SW_TTBR0_PAN=y) on a machine with support for EFI runtime
> services:
> 
>   Unable to handle kernel access to user memory outside uaccess routines
>     at virtual address 00000000f322ff30
>   Mem abort info:
>     ESR = 0x0000000096000004
>     FSC = 0x04: level 0 translation fault
>   Internal error: Oops: 0000000096000004 [#1]  SMP
>   Workqueue: efi_rts_wq efi_call_rts
>   pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>   pc : efi_call_rts+0xd8/0x288
>   Call trace:
>    efi_call_rts+0xd8/0x288 (P)
>    process_one_work+0x178/0x4f8
>    worker_thread+0x194/0x328
> 
> [...]

Applied to arm64 (for-next/mm), thanks!

[1/1] arm64/efi: Avoid voluntary preemption with efi_mm installed
      https://git.kernel.org/arm64/c/e98a9d014637

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
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