Re: [cocci] spatch 1.1.1 segmentation fault report

[Denis Efremov <efremov@linux.com>]

On 2/7/22 09:56, Julia Lawall wrote:
>> I checked that the problem persist on latest commit
>> b2a4b9b77157 parsing_c: print correct attributes in pretty_print_c.ml
>>
>> and bisected the crash to commit
>> 7b79a2415a8c6e8b1c39a8183bf732fdc6d00453 is the first bad commit
>> commit 7b79a2415a8c6e8b1c39a8183bf732fdc6d00453
>> Author: Corentin De Souza <corentin.de-souza@inria.fr>
>> Date:   Tue May 25 19:21:51 2021 +0200
>>
>>     parsing_c: detect macro iterators from their bodies
>>
>>     This uses the same strategy as macro statements (see
>>     https://gitlab.inria.fr/coccinelle/coccinelle/-/merge_requests/92).
>>     The goal is to do fix https://gitlab.inria.fr/coccinelle/coccinelle/-/issues/24
>>
>>     The next commit will finally fix the assign_expr rule in the parser, removing
>>     the conflicts it introduced while not breaking test
>>     assign_deref_funcall_in_macro_it.
>>
>>  parsing_c/cpp_token_c.ml | 39 ++++++++++++++++++++++++++++++---------
>>  parsing_c/parser_c.mly   |  3 ++-
>>  2 files changed, 32 insertions(+), 10 deletions(-)
> 
> Thanks for all of the investigation.  I'll take a look at this commit, but
> from the subject it seems hard to imagine how it would affect python...
> 
> Could you take a look at the core to see if indicates what function caused
> the problem?

Core was generated by `spatch segfault.cocci empty_dir'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x0000000000aa8b7e in pydecref (v=<optimized out>) at pyml_stubs.c:247
247     pyml_stubs.c: Directory not empty.
(gdb) bt
#0  0x0000000000aa8b7e in pydecref (v=<optimized out>) at pyml_stubs.c:247
#1  0x0000000000ac5cee in caml_empty_minor_heap () at minor_gc.c:409
#2  0x0000000000ac610c in caml_gc_dispatch () at minor_gc.c:475
#3  0x0000000000ac61fe in caml_check_urgent_gc (extra_root=<optimized out>, extra_root@entry=1) at minor_gc.c:572
#4  0x0000000000ac6293 in caml_alloc_small_dispatch (wosize=2, flags=flags@entry=1, nallocs=nallocs@entry=1, 
    encoded_alloc_lens=encoded_alloc_lens@entry=0x0) at minor_gc.c:516
#5  0x0000000000ac7831 in caml_alloc_small (wosize=wosize@entry=2, tag=tag@entry=0) at alloc.c:68
#6  0x0000000000acd6ef in caml_ml_out_channels_list (unit=<optimized out>) at io.c:512
#7  0x0000000000a47005 in camlStdlib__flush_all_231 () at stdlib.ml:349
#8  0x00000000005ffeaf in camlStd_exit__entry () at stdlib.ml:556
#9  0x00000000005f5199 in caml_program ()
#10 0x0000000000ae0860 in caml_start_program ()
#11 0x0000000000ae0be4 in caml_startup_common (argv=0x7ffcf50f98c8, pooling=<optimized out>, pooling@entry=0) at startup_nat.c:160
#12 0x0000000000ae0c5b in caml_startup_exn (argv=<optimized out>) at startup_nat.c:165
#13 caml_startup (argv=<optimized out>) at startup_nat.c:170
#14 caml_main (argv=<optimized out>) at startup_nat.c:177
#15 0x00000000005f3ddc in main (argc=<optimized out>, argv=<optimized out>) at main.c:44


> 
> Do you have parmap installed on your machine or are you using the bundled
> version?

I guess it's in my system:

configure: configuring package parmap
checking for OCaml findlib package parmap... found
...
cp /home/work/.opam/4.11.2/lib/parmap/parmap.cmi ocaml/parmap.cmi
if test -f /home/work/.opam/4.11.2/lib/parmap/parmap.cmx; then \
        cp /home/work/.opam/4.11.2/lib/parmap/parmap.cmx ocaml/parmap.cmx; \
fi

> 
> Could use test with the bytecode version of Coccinelle?  I think that
> would come without the --enable-opt option.
>

When I build spatch with --disable-opt there is no crash.