• Ding Hui's avatar
    efi: fix userspace infinite retry read efivars after EFI runtime services page fault · e006ac30
    Ding Hui authored
    After [1][2], if we catch exceptions due to EFI runtime service, we will
    clear EFI_RUNTIME_SERVICES bit to disable EFI runtime service, then the
    subsequent routine which invoke the EFI runtime service should fail.
    
    But the userspace cat efivars through /sys/firmware/efi/efivars/ will stuck
    and infinite loop calling read() due to efivarfs_file_read() return -EINTR.
    
    The -EINTR is converted from EFI_ABORTED by efi_status_to_err(), and is
    an improper return value in this situation, so let virt_efi_xxx() return
    EFI_DEVICE_ERROR and converted to -EIO to invoker.
    
    Cc: <stable@vger.kernel.org>
    Fixes: 3425d934 ("efi/x86: Handle page faults occurring while running EFI runtime services")
    Fixes: 23715a26 ("arm64: efi: Recover from synchronous exceptions occurring in firmware")
    Signed-off-by: default avatarDing Hui <dinghui@sangfor.com.cn>
    Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
    e006ac30
runtime-wrappers.c 14.3 KB