Re: REGRESSION: x86 vDSO: remove vdso-syms.o

From: Roland McGrath
Date: Mon Feb 11 2008 - 18:24:28 EST


> if that file is empty, it might be the effect of a Ctrl-C. I sometimes
> get that on .o files, if i Ctrl-C a highly parallel make -j at the wrong
> moment. (is this expected behavior? It's been like this for a long
> time.)

It is the known situation with the compiler since the dawn of time, yes.
It just writes the file directly, so if it dies in the middle, there's a
file with a fresh date. For things like this done in makefile commands
with >, it has forever been canonical for the anal to use:

... > $@.new
mv -f $@.new $@

which avoids the problem. The kernel makefiles are entirely haphazard
about places that do this or don't. It uglifies the commands, but avoids
the problem of freshly-dated but wrong/empty files from botched make runs.
I did not do this in cmd_vdsosym (though I did in cmd_vdso32sym, go figure).


Thanks,
Roland
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