Hi Michal,

The build system will sometimes emit shell command:

set -e;  ; scripts/basic/fixdep arch/ia64/kvm/.asm-offsets.s.d arch/ia64/kvm/asm-offsets.s '' > arch/ia64/kvm/.asm-offsets.s.tmp; rm -f arch/ia64/kvm/.asm-offsets.s.d; mv -f arch/ia64/kvm/.asm-offsets.s.tmp arch/ia64/kvm/.asm-offsets.s.cmd

which is not acceptable to bash, confirmed by:

% bash -c '; ;'
bash: -c: line 0: syntax error near unexpected token `;'
bash: -c: line 0: `; ;'

This error occurs
- very occasionally in x86 builds
- reliably in *native* ia64 -j32 builds
- never in ia64 -j1 builds

So the bug may be due to some tricky time/data dependency.

Bisect tells that 2da30e703c5a56e27249fa8b8607708123fa52f5 is the
first bad commit.

commit 2da30e703c5a56e27249fa8b8607708123fa52f5
Author: Michal Marek <mmarek@suse.cz>
Date:   Mon Jun 7 22:22:12 2010 +0200

    kbuild: Generate modules.builtin in make modules

    Generating the file in make modules_install was broken as well, because
    it didn't work in a readonly filesystem and otherwise it generated a
    root-owned file which is not wanted.

    Reported-by: Rafael J. Wysocki <rjw@sisk.pl>
    Signed-off-by: Michal Marek <mmarek@suse.cz>

Attached is the debug output with make --debug=j and bash -x.

Thanks,
Fengguang