On 03/03/2021 22:40, Johannes Berg wrote:
I think the problem is here:
#24 0x000000006080f234 in ipc_init_ids (ids=0x60c60de8 <init_ipc_ns+8>)
at ipc/util.c:119
#25 0x0000000060813c6d in sem_init_ns (ns=0x60d895bb <textbuf+91>) at
ipc/sem.c:254
#26 0x0000000060015b5d in sem_init () at ipc/sem.c:268
#27 0x00007f89906d92f7 in ?? () from /lib/x86_64-linux-
gnu/libcom_err.so.2
You're in the init of libcom_err.so.2, which is loaded by
"libnss_nis.so.2"
which is loaded by normal NSS code (getgrnam):
#40 0x00007f89909bf3a6 in nss_load_library (ni=ni@entry=0x61497db0) at
nsswitch.c:359
#41 0x00007f89909bfc39 in __GI___nss_lookup_function (ni=0x61497db0,
fct_name=<optimized out>, fct_name@entry=0x7f899089b020 "setgrent") at
nsswitch.c:467
#42 0x00007f899089554b in init_nss_interface () at nss_compat/compat-
grp.c:83
#43 init_nss_interface () at nss_compat/compat-grp.c:79
#44 0x00007f8990895e35 in _nss_compat_getgrnam_r (name=0x7f8990a2a1e0
"tty", grp=0x7ffe3e7a2910, buffer=0x7ffe3e7a24e0 "", buflen=1024,
errnop=0x7f899089eb00) at nss_compat/compat-grp.c:486
#45 0x00007f8990968b85 in __getgrnam_r (name=name@entry=0x7f8990a2a1e0
"tty", resbuf=resbuf@entry=0x7ffe3e7a2910,
buffer=buffer@entry=0x7ffe3e7a24e0 "", buflen=1024,
result=result@entry=0x7ffe3e7a2908)
at ../nss/getXXbyYY_r.c:315
You have a strange nsswitch configuration that causes all of this
(libnss_nis.so.2 -> libcom_err.so.2) to get loaded.
Now libcom_err.so.2 is trying to call sem_init(), and that gets ... tada
... Linux's sem_init() instead of libpthread's.
And then the crash.
Now, I don't know how to fix it (short of changing your nsswitch
configuration) - maybe we could somehow rename sem_init()? Or maybe we
can somehow give the kernel binary a lower symbol resolution than the
libc/libpthread.
I have not looked in depth in how the linking process works, but it
should have picked up the sem_init from the kernel library, not libc.
We are already supposed to do that regarding kernel vs libc string.h
functions - memcpy, etc.
Though for all of them the libc does the same so invoking the wrong one
does not kill you so this may have been broken for a while and we were
simply not noticing it.
johannes
--
Anton R. Ivanov
https://www.kot-begemot.co.uk/
