OpenVolume() on a partition without a filesystem, such as a raw slot a kernel or UKI is booted from, fails in cdev_mount() and returns EFI_DEVICE_ERROR. The UEFI specification prescribes EFI_UNSUPPORTED for that, and callers rely on it: systemd-stub skips EFI_UNSUPPORTED quietly but logs any other error, and its log_wait() then stalls boot by up to 10 s:
stub.c:587@load_addons: Unable to open root directory: Device error cpio.c:340@pack_cpio: Unable to open root directory: Device error (x6) Return EFI_UNSUPPORTED when no filesystem driver recognizes the device. Assisted-by: Claude:claude-opus-5-5 Signed-off-by: Johannes Schneider <[email protected]> --- efi/loader/protocols/file.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/efi/loader/protocols/file.c b/efi/loader/protocols/file.c index ea7b0df82e..bfcf14f0e0 100644 --- a/efi/loader/protocols/file.c +++ b/efi/loader/protocols/file.c @@ -30,6 +30,8 @@ #include <malloc.h> #include <dirent.h> #include <fs.h> +#include <linux/sprintf.h> +#include <xfuncs.h> #define MAX_UTF8_PER_UTF16 3 @@ -1012,6 +1014,16 @@ efi_open_volume(struct efi_simple_file_system_protocol *this, EFI_ENTRY("%p, %p", this, root); + /* No filesystem on the volume is EFI_UNSUPPORTED, not a device error */ + if (!cdev_get_mount_path(fs->cdev)) { + char *devpath = basprintf("/dev/%s", cdev_name(fs->cdev)); + bool has_fs = fs_detect(devpath, ""); + + free(devpath); + if (!has_fs) + return EFI_EXIT(EFI_UNSUPPORTED); + } + path = cdev_mount(fs->cdev); if (IS_ERR(path)) return EFI_EXIT(EFI_DEVICE_ERROR); -- 2.43.0
