On Thu, Jan 11, 2018 at 01:19:41PM +0100, Florian Weimer wrote: > On 01/11/2018 12:42 PM, Richard W.M. Jones wrote: > >If anyone notices Ruby programs which suddenly start to throw stack > >overflow errors (SystemStackError or the error message > >"stack level too deep") but*only* in the latest Rawhide (glibc >= > >2.26-9000, ruby >= 2.5.0), then I'm interested to hear from you. > > Could you reproduce this outside of Koji? Oh yes, very much so. You need absolutely latest Rawhide however (certainly of glibc & ruby, not sure what else). git clone https://github.com/libguestfs/nbdkit sudo dnf builddep nbdkit cd nbdkit ./configure make make check -C tests TESTS=test-ruby The test will fail with an error message: nbdkit: error: ruby: stack level too deep To go further with debugging it, I found the easiest way was: gdb --args src/nbdkit -f -v plugins/ruby/.libs/nbdkit-ruby-plugin.so tests/test.rb (gdb) break ec_stack_overflow (gdb) run In another window do: telnet localhost 10809 Examining the Ruby execution context (*ec) seems to show that Ruby gets confused by the use of C pthreads: machine = { stack_start = 0x7fffffffe000, <-- in the main thread stack stack_end = 0x7ffff46997e8, <-- apparently "huge" stack stack_maxsize = 8384512, which is caused just because we're running in a different thread from the main thread. What strange is how this suddenly started to happen, whereas the same code has been working fine for years. Unfortunately I cannot now downgrade glibc to "prove" this is a glibc thing, rather than what's more likely which is it's either Ruby itself or the test. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into KVM guests. http://libguestfs.org/virt-v2v _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx
