Crash in entry_equals <- find_entry_ptr <- hashmap_get <- recurse_create_git_tree

[riastradh]

git-cinnabar 0.6.3

$ git clone hg::https://www.mercurial-scm.org/repo/hg hg.git
Cloning into 'hg.git'...
warning: redirecting to https://repo.mercurial-scm.org/hg
Reading 52026 changesets
Reading and importing 52000 manifests
Reading and importing 103872 revisions of 3874 files
error: git-remote-hg died of signal 11
fatal: could not read ref refs/cinnabar/refs/heads/branches/default/tip
$ gdb /path/to/git-remote-hg ./git-remote-hg.core
GNU gdb (GDB) 8.3                                               
...
Reading symbols from /home/riastradh/pkgsrc/current/pkg/libexec/git-core/git-remote-hg...
[New process 5045]
[New process 22437]
Core was generated by `git-remote-hg'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x0000000000000000 in ?? ()
[Current thread is 1 (process 5045)]
(gdb) bt
#0  0x0000000000000000 in ?? ()
#1  0x0000000024daf857 in entry_equals (map=0x252d19c0 <git_tree_cache>,
    map=0x252d19c0 <git_tree_cache>, keydata=0x0, e2=0x7f7fff5cdb80,
    e1=<optimized out>)
    at /home/riastradh/pkgsrc/current/work/devel/git-cinnabar/work/git-cinnabar-0.6.3/git-core/hashmap.c:101
#2  find_entry_ptr (keydata=0x0, key=0x7f7fff5cdb80,
    map=0x252d19c0 <git_tree_cache>)
    at /home/riastradh/pkgsrc/current/work/devel/git-cinnabar/work/git-cinnabar-0.6.3/git-core/hashmap.c:140
#3  hashmap_get (map=map@entry=0x252d19c0 <git_tree_cache>,
    key=key@entry=0x7f7fff5cdb80, keydata=keydata@entry=0x0)
    at /home/riastradh/pkgsrc/current/work/devel/git-cinnabar/work/git-cinnabar-0.6.3/git-core/hashmap.c:218
#4  0x0000000024d52557 in recurse_create_git_tree (
    tree_id=tree_id@entry=0x7f7fff5cdf90, reference=0x7f7fff5cde50,
    merge_tree_id=0x0, result=result@entry=0x7f7fff5cde10,
    cache=0x252d19c0 <git_tree_cache>)
    at /home/riastradh/pkgsrc/current/work/devel/git-cinnabar/work/git-cinnabar-0.6.3/src/cinnabar-helper.c:750
#5  0x0000000024d524b6 in recurse_create_git_tree (tree_id=0x7f7fff5ce7e0,
    reference=0x7f7fff5ce564, merge_tree_id=0x0, result=0x7f7fff5ce5e0,
    cache=0x252d19c0 <git_tree_cache>)
    at /home/riastradh/pkgsrc/current/work/devel/git-cinnabar/work/git-cinnabar-0.6.3/src/cinnabar-helper.c:797
#6  0x0000000024cb73eb in git_cinnabar::store::store_changegroup ()
#7  0x0000000024cd8efe in git_cinnabar::hg_connect::get_store_bundle ()
#8  0x0000000024d29e64 in git_cinnabar::remote_helper_import ()
#9  0x0000000024d34906 in git_cinnabar::git_remote_hg ()
#10 0x0000000024d1dec3 in git_cinnabar::git_cinnabar ()
#11 0x0000000024d39c28 in cinnabar_main ()
#12 0x0000000024d1f8b4 in git_cinnabar::main ()
#13 0x0000000024c472c3 in std::sys_common::backtrace::__rust_begin_short_backtrace ()
#14 0x000078bde4357010 in ?? ()
#15 0x0000000024c5ecf9 in std::rt::lang_start::{{closure}} ()
#16 0x000078bde4357010 in ?? ()
#17 0x0000000024fa5125 in std::rt::lang_start_internal ()
#18 0x0000000024d49835 in main ()

[riastradh]

Worked fine in 0.6.2 + patch to fix #315.

[riastradh]

Looks like something is calling into create_git_tree before git_tree_cache has been initialized.

[glandium]

I can't reproduce with 0.6.3. Would you be able to record your crash with rr?

[riastradh]

What is rr and how do I record it?

[glandium]

https://rr-project.org/

[riastradh]

CMake Error at CMakeLists.txt:338 (message):
  Couldn't find linux/seccomp.h.  You may need to upgrade your kernel.

Is rr linux-only? This is on NetBSD.

[glandium]

Yes, rr is linux-only.

[riastradh]

I can share more information out of the core dump if that would be helpful. For example:

(gdb) print git_tree_cache 
$1 = {table = 0x7a5921f42c00, cmpfn = 0x0, cmpfn_data = 0x0, private_size = 0, 
  tablesize = 64, grow_at = 51, shrink_at = 0, do_count_items = 0}
(gdb) print nongit 
$2 = 1
(gdb) print initialized
$3 = <optimized out>
(gdb) print metadata_oid
$4 = {hash = '\000' <repeats 31 times>, algo = 0}

[glandium]

That state of git_tree_cache makes no sense.