mjhjmtu

Since yesterday, I can no longer launch qemu with an external kernel compiled on my laptop (running Arch Linux).

If I compile a vanilla Linux kernel (version 4.13, from Linus Torvalds' github repo), then try to boot qemu this way:

qemu-system-x86_64 --enable-kvm -boot c -kernel arch/x86/boot/bzImage

This starts the display, showing this SeaBIOS output refreshing every 2-3 seconds:

 Booting from ROM...
 Probing EDD (edd=off to disable)... ok
 early console in extract_kernel
 input_data: 0x0000000002c773b4
 input_len: 0x000000000090c470
 output: 0x0000000001000000
 output_len: 0x000000000173a968
 kernel_total_size: 0x00000000025a7000

 Decompressing Linux... Parsing ELF...

If I add these flags to qemu to enable SeaBIOS debugging output:

-chardev stdio,id=seabios -device isa-debugcon,iobase=0x402,chardev=seabios

I get this output that keeps repeating: https://pastebin.com/mZKeM6r5

Funny thing, if I compile the same kernel, with the same configuration file on another machine (running Debian) and copy the bzImage to my machine, it boots just fine. So I guess something happened in my toolchain. There was an update of gcc recently, but going back to the previous version of the package (the one I had when there was no problem) does not solve my problem.

As a temporary workaround, I thought I could compile on the Debian machine using distcc to avoid copying files back and forth, but the problem still occurs, so I guess the problem is in the final steps of the compilation process (from linkage to the end, since these happen on my laptop).

Additional info:

• 
  gcc version on my laptop (ArchLinux): 8.2.0 (pkg version = 8.2.0-2)


• 
  gcc version on my Debian machine: 6.3.0 (pkg version = 4:6.3.0-4)

Edit: completed SeaBIOS output

I had the same problem. In my case, it was caused by the binutils update to 2.31. Judging from the date you posted your question, it's not unlikely that you had just installed the arch linux binutils update to 2.31 from August 2nd, which matches nicely.

You need this commit for kernels earlier than 4.16.

binutils 2.31 has changed the defaults of the linker (ld) such that the default for max-page-size was decreased from 2MiB to 4kiB. This change breaks the x86_64 kernel, unless said commit is applied.