URL: <https://savannah.gnu.org/bugs/?58498>
Summary: GRUB cannot correctly boot kFreeBSD i386 from ZFS Project: GNU GRUB Submitted by: whr Submitted on: Thu 04 Jun 2020 03:01:25 PM UTC Category: Booting Severity: Major Priority: 5 - Normal Item Group: Software Error Status: None Privacy: Public Assigned to: None Originator Name: WHR Originator Email: msl0000023...@gmail.com Open/Closed: Open Release: Release: Git master Discussion Lock: Any Reproducibility: Every Time Planned Release: None _______________________________________________________ Details: This issue can be reproduced with GRUB version 2.02 and 2.04, and I believe it exists in the latest source repository as well; unfortunately I can't select '2.04' in 'Release:' combo box on this page. The kFreeBSD versions I tested are 10.1-RELEASE, 10.3-RELEASE, 11.1-RELEASE-p15, 12.0-RELEASE, 12.0-RELEASE-p5, 12.0-RELEASE-p9 and 12.0-RELEASE-p10. == To reproduce == * Install a FreeBSD i386 system with ZFS root. * Install GRUB (i386-pc) by building it from source, and run *grub-install(8)* to install it to hard disk. * Create a *grub.cfg* by either running *grub-mkconfig(8)* or manually writing one. * Reboot the machine and select to boot FreeBSD from GRUB menu. === Simplified configuration example === > menuentry "FreeBSD i386" --class freebsd --class bsd --class os { > insmod part_gpt > insmod zfs > set root=hd0,gpt3 > search --set root --label zroot > echo "Loading FreeBSD kernel ..." > kfreebsd /ROOT/default@/boot/kernel/kernel > kfreebsd_loadenv /ROOT/default@/boot/device.hints > kfreebsd_module_elf /ROOT/default@/boot/kernel/opensolaris.ko > kfreebsd_module_elf /ROOT/default@/boot/kernel/zfs.ko > } == Result == The system hang soon after GRUB jumps to kFreeBSD entry point, there is no console output from kFreeBSD. == Cause == GRUB source file 'grub-core/loader/i386/bsd.c' contains the following code in function 'grub_freebsd_boot': > stack[1] = bootflags | FREEBSD_RB_BOOTINFO; > stack[2] = freebsd_bootdev; > stack[3] = freebsd_zfsguid ? 4 : 0; > stack[4] = freebsd_zfsguid; > stack[5] = freebsd_zfsguid >> 32; > stack[6] = stack_target + 9 * sizeof (grub_uint32_t); > stack[7] = bi.tags; > stack[8] = kern_end; it prepare the arguments to be passed to the entry point of the kernel ('btext' in kFreeBSD image); the arguments 3, 4 and 5 are incorrect, because according to the corresponding FreeBSD source code (https://svnweb.freebsd.org/base/stable/12/sys/i386/i386/locore.s?revision=339434&view=markup#l178), those 3 arguments should always be set to 0 to distinguish from old boot protocols, otherwise the kernel would just halt as they assumed it was booted with an unsupported boot protocol (https://svnweb.freebsd.org/base/stable/12/sys/i386/i386/locore.s?revision=339434&view=markup#l214). Since the boot protocol check exists only in kFreeBSD i386, and 'freebsd_zfsguid' will be 0 if current 'root' device in GRUB isn't a ZFS vdev, this bug only shown when booting kFreeBSD i386 with from ZFS. == Proposed fix == I removed 'freebsd_zfsguid' variable and codes that used it. Passing a ZPOOL GUID to the kernel would be completely useless, as the kernel didn't use it in anyways, but instead chokes on it. The attached diff file is generated from the latest commit in 'master' branch of GRUB Git repository. _______________________________________________________ File Attachments: ------------------------------------------------------- Date: Thu 04 Jun 2020 03:01:25 PM UTC Name: grub-kfreebsd-i386-zfs-hang-fix.diff Size: 2KiB By: whr <http://savannah.gnu.org/bugs/download.php?file_id=49213> _______________________________________________________ Reply to this item at: <https://savannah.gnu.org/bugs/?58498> _______________________________________________ Message sent via Savannah https://savannah.gnu.org/