Roman Bolshakov <r.bolsha...@yadro.com> writes: > On Sat, May 29, 2021 at 09:39:49AM +1000, Michael Ellerman wrote: >> Roman Bolshakov <r.bolsha...@yadro.com> writes: >> > This reverts commit b0b3b2c78ec075cec4721986a95abbbac8c3da4f. >> > >> > Otherwise, direct kernel boot with initramfs no longer works in QEMU. >> > It's broken in some bizarre way because a valid initramfs is not >> > recognized anymore: >> > >> > Found initrd at 0xc000000001f70000:0xc000000003d61d64 >> > rootfs image is not initramfs (XZ-compressed data is corrupt); looks >> > like an initrd >> > >> > The issue is observed on v5.13-rc3 if the kernel is built with >> > defconfig, GCC 7.5.0 and GNU ld 2.32.0. >> >> Are you able to try a different compiler? > > Hi Michael, > > I've just tried GCC 9.3.1 and the result is the same. > > The offending patch has assembly inlines, they typically go through > binutils/GAS and it might also be a case when older binutils doesn't > implement something properly (i've seen this on x86 and arm).
Jump labels use asm goto, which is a compiler feature, but you're right that the binutils version could also be important. What ld versions have you tried? And are those the toolchains from kernel.org or somewhere else? >> I test booting qemu constantly, but I don't use GCC 7.5. >> >> And what qemu version are you using? >> > > QEMU 3.1.1, but I've also tried 6.0.50 (QEMU master, 62c0ac5041e913) and > it fails the same way. OK. >> I assume your initramfs is compressed with XZ? How large is it >> compressed? >> > > Yes, XZ. initramfs size is 30 MB (around 100 MB cpio size). > > It's interesting that the issue doesn't happen if I pass initramfs from > host (11MB), then the initramfs can be recognized. It might be related > to initramfs size then and bigger initramfs that used to work no longer > work with v5.13-rc3. Are you using qemu's -initrd option to pass the initramfs, or are you building the initramfs into the kernel? > So, I've created a small initramfs using only static busybox (2.7M > uncompressed, 960K compressed with xz). No error is produced and it > boots fine. > > If I add a dummy file (11M off /dev/urandom) to the small busybox > initramfs, it boots and the init is started but I'm seeing the error: > > rootfs image is not initramfs (XZ-compressed data is corrupt); looks like > an initrd > > sha1sum of the file inside initramfs doesn't match sha1sum on the host. > > guest # sha1sum dummy > 407c347e671ddd00f69df12b3368048bad0ebf0c dummy > # QEMU: Terminated > host $ sha1sum dummy > ed8494b3eecab804960ceba2c497270eed0b0cd1 dummy > > sha1sum is the same in the guest and on the host for 10M dummy file: > > guest # sha1sum dummy > 43855f7a772a28cce91da9eb8f86f53bc807631f dummy > # QEMU: Terminated > host $ sha1sum dummy > 43855f7a772a28cce91da9eb8f86f53bc807631f dummy > > That might explain why bigger initramfs (or initramfs with bigger files) > doesn't boot - because some files might appear corrupted inside the guest. > > Here're the sources of the initrd along with 11M dummy file: > https://drive.yadro.com/s/W8HdbPnaKmPPwK4 > > I've compressed it with: > $ find . 2>/dev/null | cpio -ocR 0:0 | xz --check=crc32 > > ../initrd-dummy.xz > > Hope this helps, I haven't been able to reproduce any corruption, with various initramfs sizes. Can you send us your kernel .config & qemu command line. And can you try the patch below? cheers diff --git a/arch/powerpc/kernel/jump_label.c b/arch/powerpc/kernel/jump_label.c index ce87dc5ea23c..3d9878124cde 100644 --- a/arch/powerpc/kernel/jump_label.c +++ b/arch/powerpc/kernel/jump_label.c @@ -13,6 +13,9 @@ void arch_jump_label_transform(struct jump_entry *entry, { struct ppc_inst *addr = (struct ppc_inst *)jump_entry_code(entry); + if (!is_kernel_text((unsigned long)addr) && !is_kernel_inittext((unsigned long)addr)) + printk("%s: addr %px %pS is not kernel text?\n", __func__, addr, addr); + if (type == JUMP_LABEL_JMP) patch_branch(addr, jump_entry_target(entry), 0); else