#2427 SEGV on vfprintf

[liuchenyifan]

gnuplot 5.5 (last modified in 9.18) on centos linux 7.7.1908

information below from valgrind:
==4193== Memcheck, a memory error detector
==4193== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==4193== Using Valgrind-3.16.1 and LibVEX; rerun with -h for copyright info
==4193== Command: /root/pfuzz-new/p-fuzz/pfcon/programs/gnuplot ./gnuplot/task1/id:000000,sig:11,src:1192782120+001081,op:splice,rep:2
==4193==

"./gnuplot/task1/id:000000,sig:11,src:1192782120+001081,op:splice,rep:2" line 1: warning: ==4193== Invalid read of size 4
==4193== at 0x61512ED: vfprintf (in /usr/lib64/libc-2.17.so)
==4193== by 0x6154E5A: buffered_vfprintf (in /usr/lib64/libc-2.17.so)
==4193== by 0x614F81D: vfprintf (in /usr/lib64/libc-2.17.so)
==4193== by 0x82F69D: int_warn (util.c:1225)
==4193== by 0x498892: df_open (datafile.c:1438)
==4193== by 0x61ABBF: eval_plots (plot2d.c:2218)
==4193== by 0x44BB88: plot_command (command.c:1897)
==4193== by 0x4411AB: command (command.c:659)
==4193== by 0x4411AB: do_line (command.c:429)
==4193== by 0x5CD14B: load_file (misc.c:335)
==4193== by 0x406416: main (plot.c:636)
==4193== Address 0x1fff001000 is not stack'd, malloc'd or (recently) free'd
==4193==
==4193==
==4193== Process terminating with default action of signal 11 (SIGSEGV)
==4193== Access not within mapped region at address 0x1FFF001000
==4193== at 0x61512ED: vfprintf (in /usr/lib64/libc-2.17.so)
==4193== by 0x6154E5A: buffered_vfprintf (in /usr/lib64/libc-2.17.so)
==4193== by 0x614F81D: vfprintf (in /usr/lib64/libc-2.17.so)
==4193== by 0x82F69D: int_warn (util.c:1225)
==4193== by 0x498892: df_open (datafile.c:1438)
==4193== by 0x61ABBF: eval_plots (plot2d.c:2218)
==4193== by 0x44BB88: plot_command (command.c:1897)
==4193== by 0x4411AB: command (command.c:659)
==4193== by 0x4411AB: do_line (command.c:429)
==4193== by 0x5CD14B: load_file (misc.c:335)
==4193== by 0x406416: main (plot.c:636)
==4193== If you believe this happened as a result of a stack
==4193== overflow in your program's main thread (unlikely but
==4193== possible), you can try to increase the size of the
==4193== main thread stack using the --main-stacksize= flag.
==4193== The main thread stack size used in this run was 8388608.
==4193==
==4193== HEAP SUMMARY:
==4193== in use at exit: 13,127,929 bytes in 172 blocks
==4193== total heap usage: 284 allocs, 112 frees, 13,807,407 bytes allocated
==4193==
==4193== LEAK SUMMARY:
==4193== definitely lost: 0 bytes in 0 blocks
==4193== indirectly lost: 0 bytes in 0 blocks
==4193== possibly lost: 0 bytes in 0 blocks
==4193== still reachable: 13,127,929 bytes in 172 blocks
==4193== suppressed: 0 bytes in 0 blocks
==4193== Rerun with --leak-check=full to see details of leaked memory
==4193==
==4193== For lists of detected and suppressed errors, rerun with: -s
==4193== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

[Ethan Merritt]

Does not fail using current git tip
Probably fixed since your 9.18 2020 executable