The call to snprintf() as was used is wrong: we use the return value to
advance output, but the man page says
> The functions snprintf() and vsnprintf() do not write more than size
> bytes (including the terminating null byte ('\0')). If the output was
> truncated due to this limit, then the return value is the number of
> characters (excluding the terminating null byte) which would have been
> written to the final string if enough space had been available.
> Thus, a return value of size or more means that the output was
> truncated.
Thus, output could go beyond end, and we get a stack overflow. Instead,
encapsulate the call to snprintf() checking this condition, and only
advancing output as intended, limiting to 0 if we are at the end of the
buffer. This avoids this error:
==964825==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7be799f51988 at pc 0x7fe7d66b0d39 bp 0x7be79b825ef0 sp 0x7be79b8256c0
WRITE of size 3 at 0x7be799f51988 thread T24
#0 0x7fe7d66b0d38 in vsnprintf (/lib64/libasan.so.8+0xb0d38) (BuildId: 10b8ccd49f75c21babf1d7abe51bb63589d8471f)
#1 0x7fe7d66b2d44 in snprintf (/lib64/libasan.so.8+0xb2d44) (BuildId: 10b8ccd49f75c21babf1d7abe51bb63589d8471f)
#2 0x0000008fe7c6 in dump_mac_stats /home/richie/w/refactor-dlsch/openair2/LAYER2/NR_MAC_gNB/main.c:183
#3 0x00000092071a in gNB_dlsch_ulsch_scheduler /home/richie/w/refactor-dlsch/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler.c:200
#4 0x0000008f8f78 in run_scheduler_monolithic /home/richie/w/refactor-dlsch/openair2/NR_PHY_INTERFACE/NR_IF_Module.c:399
Robert Schmidt
48faffc131