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Re: Compiler segfault when building the kernel




On Tue, Jun 13, 2017 at 11:57:55AM -0400, Celejar wrote:
> On Mon, 12 Jun 2017 10:45:17 +0300
> Adrian Bunk <bunk@xxxxxxxxxx> wrote:
> 
> > On Fri, Jun 09, 2017 at 07:58:12AM -0400, Celejar wrote:
> > > Hi,
> > > 
> > > I've been building kernels (vanilla from upstream) for years with
> > > kernel-package (typical command line: "time make-kpkg -j2 --initrd
> > > --revision 1.custom kernel_image"; .kernel-pkg.conf contains just the
> > > line "root_cmd = fakeroot") without problem. Recently, the builds have
> > > begun to fail with messages like these:
> 
> ...
> 
> > > > ./include/linux/rcu_sync.h:29:48: internal compiler error: Segmentation fault
> > > >  enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC };
> > > >                                                 ^
> > > > Please submit a full bug report,
> > > > with preprocessed source if appropriate.
> > > > See <file:///usr/share/doc/gcc-4.9/README.Bugs> for instructions.
> > > >   CC      fs/posix_acl.o
> > > > The bug is not reproducible, so it is likely a hardware or OS problem.
> 
> ...
> 
> > > This occurred immediately following a cleaning of the source tree
> > > ("make-kpkg ... clean"), the first one I've done in quite some time, so
> > > I'm pretty sure that that's what triggered this, whatever the
> > > underlying problem actually is.
> > > 
> > > Googling suggests that this sort of thing can be triggered by race
> > > conditions caused by build systems improper handling of
> > > concurrency,e.g.:
> > > 
> > > https://askubuntu.com/questions/343490/the-bug-is-not-reproducible-so-it-is-likely-a-hardware-or-os-problem
> > 
> > That is just an incorrect answer from some random person.
> > 
> > Missing dependencies produce different kinds of errors,
> > never internal compiler errors.
> 
> The suggestion is not that the bug is caused by the missing
> dependencies, but rather that there's an underlying bug getting hit,
> and the fact that it's not reporducible is due to a race condition
> caused by improper concurrency handling.
>...

I fully understand this suggestion - I have seen (and fixed) countless 
cased of such dependency issues.

The errors they cause are different.

"internal compiler error that is not 100% reproducible" - at that point 
it is nearly certain that the underlying problem is a hardware problem.

> Celejar

cu
Adrian

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       "Only a promise," Lao Er said.
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