Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> writes:
> I'm building for a ppc32 (mpc8309) target using Yocto, and I'm hitting a
> very hard to debug problem that maybe someone else has encountered. This
> doesn't happen always, perhaps 1 in 8 times or something like that.
>
> The issue is that when the build gets to do "${CROSS}objcopy -O binary
> ... vmlinux", vmlinux is not (no longer) a proper ELF file, so naturally
> that fails with
>
> powerpc-oe-linux-objcopy:vmlinux: file format not recognized
>
> So I hacked link-vmlinux.sh to stash copies of vmlinux before and after
> sortextable vmlinux. Both of those are proper ELF files, and comparing
> the corrupted vmlinux to vmlinux.after_sort they are identical after the
> first 52 bytes; in vmlinux, those first 52 bytes are all 0.
>
> I also saved stat(1) info to see if vmlinux is being replaced or
> modified in-place.
>
> $ cat vmlinux.stat.after_sort
> File: 'vmlinux'
> Size: 8608456 Blocks: 16696 IO Block: 4096 regular file
> Device: 811h/2065d Inode: 21919132 Links: 1
> Access: (0755/-rwxr-xr-x) Uid: ( 1000/ user) Gid: ( 1001/ user)
> Access: 2020-01-22 10:52:38.946703081 +0000
> Modify: 2020-01-22 10:52:38.954703105 +0000
> Change: 2020-01-22 10:52:38.954703105 +0000
>
> $ stat vmlinux
> File: 'vmlinux'
> Size: 8608456 Blocks: 16688 IO Block: 4096 regular file
> Device: 811h/2065d Inode: 21919132 Links: 1
> Access: (0755/-rwxr-xr-x) Uid: ( 1000/ user) Gid: ( 1001/ user)
> Access: 2020-01-22 17:20:00.650379057 +0000
> Modify: 2020-01-22 10:52:38.954703105 +0000
> Change: 2020-01-22 10:52:38.954703105 +0000
>
> So the inode number and mtime/ctime are exactly the same, but for some
> reason Blocks: has changed? This is on an ext4 filesystem, but I don't
> suspect the filesystem to be broken, because it's always just vmlinux
> that ends up corrupt, and always in exactly this way with the first 52
> bytes having been wiped.
>
> Any ideas?
Not really sorry. Haven't seen or heard of that before.
Are you doing a parallel make? If so does -j 1 fix it?
If it seems like sortextable is at fault then strace'ing it would be my
next step.
cheers
