On Mon, Dec 19, 2022 at 4:13 AM Johan Hovold <johan+linaro@xxxxxxxxxx> wrote: > > Do not try to refresh the RNG seed in case the firmware does not support > setting variables. > > This is specifically needed to prevent a NULL-pointer dereference on the > Lenovo X13s with some firmware revisions, or more generally, whenever > the runtime services have been disabled (e.g. efi=noruntime or with > PREEMPT_RT). > > Fixes: e7b813b32a42 ("efi: random: refresh non-volatile random seed when RNG is initialized") > Reported-by: Steev Klimaszewski <steev@xxxxxxxx> > Reported-by: Bjorn Andersson <andersson@xxxxxxxxxx> > Tested-by: Andrew Halaney <ahalaney@xxxxxxxxxx> # sc8280xp-lenovo-thinkpad-x13s > Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx> > --- > > Changes in v2 > - amend commit message with a comment on this being needed whenever the > runtime services have been disabled > > > drivers/firmware/efi/efi.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index 31a4090c66b3..09716eebe8ac 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -429,7 +429,9 @@ static int __init efisubsys_init(void) > platform_device_register_simple("efi_secret", 0, NULL, 0); > #endif > > - execute_with_initialized_rng(&refresh_nv_rng_seed_nb); > + if (efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE)) > + execute_with_initialized_rng(&refresh_nv_rng_seed_nb); > + > return 0; > > err_remove_group: > -- > 2.37.4 > Andrew already sent one, but also confirming since I reported it, this fixes the issue for me as well. Tested-by: Steev Klimaszewski <steev@xxxxxxxx>