Bug #6190
closedwarning: 'tmp_first_tfi' may be used uninitialized [-Wmaybe-uninitialized]
0%
Description
Seen when building recent osmo-pcu with gcc v13.2.1:
In file included from ../../../src/osmo-pcu/src/gprs_debug.h:21,
from ../../../src/osmo-pcu/src/tbf.h:26,
from ../../../src/osmo-pcu/src/pdch.h:31,
from ../../../src/osmo-pcu/src/bts.h:20,
from ../../../src/osmo-pcu/src/bts.cpp:21:
../../../src/osmo-pcu/src/bts.cpp: In function 'int bts_tfi_find_free(const gprs_rlcmac_bts*, gprs_rlcmac_tbf_direction, uint8_t*, int8_t)':
/opt/osmocom/include/osmocom/core/logging.h:107:42: warning: 'tmp_first_tfi' may be used uninitialized [-Wmaybe-uninitialized]
107 | logp_stub(__FILE__, __LINE__, cont, fmt, ##args); \
| ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/osmocom/include/osmocom/core/logging.h:85:9: note: in expansion of macro 'LOGPSRCC'
85 | LOGPSRCC(ss, level, caller_file, caller_line, 0, fmt, ##args)
| ^~~~~~~~
/opt/osmocom/include/osmocom/core/logging.h:50:9: note: in expansion of macro 'LOGPSRC'
50 | LOGPSRC(ss, level, NULL, 0, fmt, ## args)
| ^~~~~~~
../../../src/osmo-pcu/src/bts.cpp:663:9: note: in expansion of macro 'LOGP'
663 | LOGP(DRLCMAC, LOGL_DEBUG, "Found first unallocated TRX=%d TFI=%d\n",
| ^~~~
../../../src/osmo-pcu/src/bts.cpp:645:25: note: 'tmp_first_tfi' was declared here
645 | uint8_t tmp_first_tfi;
| ^~~~~~~~~~~~~
Updated by pespin 7 months ago
- Assignee changed from pespin to fixeria
I cannot reproduce it using the same gcc version (Arch).
Furthermore, my analysis of trx_count_free_tfi concludes that tmp_first_tfi is always set, so it would be a false positive.
Please fixeria feel free to take care of this yourself by submitting a patch since you are the one getting the error if it hurts you. It's probably a matter of nitializing the variable to make gcc happy.
Updated by fixeria 7 months ago
BTW, I am seeing exactly the same error in Jenkins build logs:
https://jenkins.osmocom.org/jenkins/job/gerrit-binpkgs/2069/consoleFull [almalinux:8]
CC pcuif_sock.lo
In file included from ./coding_scheme.h:18,
from ./pdch.h:26,
from ./bts.h:20,
from bts.cpp:21:
/usr/include/libosmocore/osmocom/core/utils.h: In function 'int bts_tfi_find_free(const gprs_rlcmac_bts*, gprs_rlcmac_tbf_direction, uint8_t*, int8_t)':
/usr/include/libosmocore/osmocom/core/utils.h:115:2: warning: 'tmp_first_tfi' may be used uninitialized in this function [-Wmaybe-uninitialized]
if (OSMO_UNLIKELY(!(exp))) { \
^~
bts.cpp:645:11: note: 'tmp_first_tfi' was declared here
uint8_t tmp_first_tfi;
^~~~~~~~~~~~~
Updated by fixeria 7 months ago
- Status changed from New to Feedback
The workaround initializing tmp_first_tfi to 0xff (invalid value) is here:
https://gerrit.osmocom.org/c/osmo-pcu/+/34533 bts: bts_tfi_find_free(): fix -Wmaybe-uninitialized (false positive)
