Discussion related to cado-nfs

[Emmanuel Thomé <Emmanuel.Thome@inria.fr>]

Hi,

Thanks for your report.

Issue tracked here: https://gitlab.inria.fr/cado-nfs/cado-nfs/-/issues/30023

I need to investigate, because it seems to be quite an intricate
situation. I think that we're still seeing the fallout of bug #30012 and
the different merge requests that followed.

Note that bkthresh1 should very much be production quality, given its
major importance in our latest computational records. But yes, some
recent modifications of the code apparently don't work well with it, and
this must be fixed.

Best regards,

E.

On Tue, Nov 09, 2021 at 08:23:23PM +0000, Robert Balfour wrote:
> Dear all,
> 
> The rarely used -bkthresh1 option in las leads to a crash in the latest
> CADO revision, as long as the threshold used is high enough. The bug
> appears to be relatively new, as I could not reproduce it with revision
> 271ad1f8 from two months ago; possibly it was brought in with
> reduce-plattice?
> 
> For example, with the attached polynomial file, running the command
> 
> las -poly ../../cadojobs/3_748+_clients/download/3_748plus.poly -q0
> 100000000 -A 30 -nq 20 -lim0 500000000 -lim1 300000000 -lpb0 33 -lpb1 34
> -mfb0 66 -mfb1 98 -ncurves0 25 -ncurves1 20 -bkthresh1 100000000 -fb1
> ../../cadojobs/3_748+_clients/download/3_748plus.roots1.gz -out
> ../../cadojobs/sievertest/3_748plus.100M.bkthresh1 -t 4 -stats-stderr
> 
> quickly leads to the following:
> 
> # Error, p = 6440821 does not divide at (N,x) = (256,16509)
> *** Error: caught signal "Aborted"
> ======= Backtrace: =========
> las(+0x291074) [0x55f651618074]
> /lib/x86_64-linux-gnu/libc.so.6(+0x46210) [0x7fc693131210]
> /lib/x86_64-linux-gnu/libc.so.6(gsignal+0xcb) [0x7fc69313118b]
> /lib/x86_64-linux-gnu/libc.so.6(abort+0x12b) [0x7fc693110859]
> las(_Z19divide_known_primesRSt6vectorImSaImEER7cxx_mpzjjbP15bucket_primes_tP21bucket_array_completeRK13trialdiv_datalmRKN13fb_factorbase7slicingE+0xe7d)
> [0x55f65152c3fd]
> las(_ZN25process_bucket_region_run16cofactoring_syncERSt6vectorItSaItEE+0x1485)
> [0x55f6514c8105]
> las(_ZN25process_bucket_region_runclEv+0x4dd) [0x55f6514ca53d]
> las(_ZN27process_bucket_region_spawnclEP13worker_threadi+0x146)
> [0x55f6514ca946]
> las(_ZN11thread_pool16call_shared_taskI27process_bucket_region_spawnEEP11task_resultP13worker_threadP15task_parametersi+0x1d)
> [0x55f6514cf0fd]
> las(_ZN11thread_pool20thread_work_on_tasksER13worker_thread+0x91)
> [0x55f651607a61]
> las(_ZN11thread_pool27thread_work_on_tasks_staticEPv+0x13) [0x55f651607b33]
> /lib/x86_64-linux-gnu/libpthread.so.0(+0x9609) [0x7fc693938609]
> /lib/x86_64-linux-gnu/libc.so.6(clone+0x43) [0x7fc69320d293]
> Aborted (core dumped)
> 
> I have also attached the output file.
> 
> Best regards,
> Robert