[lfs-dev] kernel messages during gcc tests

Bruce Dubbs bruce.dubbs at gmail.com
Wed Feb 3 12:10:19 PST 2016

ALZ (phyglos.org) wrote:
> Hi Bruce, all,
> I'm also updating my scripts to last versions. Here, my two cents.
> On 02/03/2016 05:36 AM, Bruce Dubbs wrote:
>> I just updated several packages in LFS and did a complete LFS build
>> including all Chapter 6 tests.One thing I noticed that I haven't seen
>> before is a ton of error messages in /var/log/kern.log.  The look like:
>> Feb  2 20:52:05 lfs78 kernel: [1888937.495544] lib-42.exe[6559]:
>> segfault at 8 ip 00007f63a68c1fbe sp 00007fffd02bbde0 error 4 in
>> libgomp.so.1.0.0[7f63a68ab000+1f000]
> I've noticed some random failures at different tests from GCC in several
> runs of my scripts (probably after upgrading to gcc 5.3.0, but I cannot
> confirm anything). I'm building with all tests switched on in all packages.
> Here is the first example of what I've found in /var/log>/kern.log after
> reading your message.
> Jan 30 10:09:12 PCALZ8phy kernel: [128479.612812] lib-42.exe[10783]:
> segfault at 8 ip 00007f0d2eff4ffe sp 00007ffeadf9f880 error 4 in
> libgomp.so.1.0.0[7f0d2efde000+1f000]
>> In addition to segfaults, there are some messages about 'trap invalid
>> opcode' in overflow-add-4.exe.
> Feb  2 21:13:05 PCALZ8phy kernel: [49354.387702] traps:
> overflow-add-4.[20088] trap invalid opcode ip:400683 sp:7ffde7b954d8
> error:0 in overflow-add-4.exe[400000+1000]
>>  From the time stamps, I traced these to the gcc testuite.  The test log
>> does not show anything unusual.  There are two unexpected failures in
>> libstdc++:
>> FAIL: experimental/filesystem/iterators/directory_iterator.cc
>> FAIL: experimental/filesystem/iterators/recursive_directory_iterator.cc
> Libstdc++ are the random, unexpected failures at GCC tests that caught my
> attention but I was just focusing in updating my scripts.
>> But I've seen those before.
>> Overall the build seems to have been normal.
> I once had a total freeze of my VM and had to revert back to a stable
> snapshot to continue updating. (I remember some "kernel errors" in the
> screen but I didn't jot down anything)
>> A couple of things to consider is that it may be a HW issue on my
>> system.  It's a new Skylake i5, so gcc may be making the wrong
>> assumptions about instruction set.  I can check this out on an Haswell
>> i7 to see if it happens there.
>> Overall, these may just artifacts in the gcc test procedure, but has
>> anyone else seen anything like this?

> I'm planning to run full LFS builds this weekend with last packages
> versions both in VM and physical machine. Should this issues repeat
> consistently with the new updated scripts, I'll report back.

Thanks.  I did do a jhalfs build on my i7 and got the same kernel messages 
that are what you listed above.  I suppose they are normal, but just not 
noticed before.  They do not appear on the screen.

   -- Bruce

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