[Sssd-maintainers] [Bug 1886816] [abrt] sssd-common: sss_mmap_cache_pw_store(): sssd_nss killed by SIGBUS

https://bugzilla.redhat.com/show_bug.cgi?id=1886816

--- Comment #14 from Alexey Tikhonov  ---
Program terminated with signal SIGBUS, Bus error.
#0  0x000055b728aceb15 in sss_mmap_cache_pw_store
(_mcc=_mcc@entry=0x55b72a00dd28, name=0x55b72a030380,
pw=pw@entry=0x7fff947313c0, uid=uid@entry=173, gid=gid@entry=173,
gecos=gecos@entry=0x7fff947313d0, homedir=0x7fff947313e0, shell=0x7fff947313f0)
at src/responder/nss/nsssrv_mmap_cache.c:769

This ^^ is `MC_RAISE_BARRIER(rec);`:
```
#define MC_RAISE_BARRIER(m) do { \
    m->b2 = MC_NEXT_BARRIER(m->b1); \
    __sync_synchronize(); \
} while (0)
```

In "open_fds" there is:
```
17:/var/lib/sss/mc/passwd (deleted)
pos:    0
flags:  02100000
mnt_id: 65

18:/var/lib/sss/mc/passwd
pos:    0
flags:  0100002
mnt_id: 65
lock:   1: POSIX  ADVISORY  WRITE 710 00:20:429251 0 0
```
  --  seems SIGBUS was triggered by attempt to access memory mmap-ed to deleted
file.

Is there any chance this file ("/var/lib/sss/mc/passwd") was deleted by some
outer process?