#2328 SEGV on plot_points

[liuchenyifan]

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

information below from valgrind
==2306== Invalid read of size 8
==2306== at 0x535C31: plot_points (graphics.c:2333)
==2306== by 0x55DFB7: do_plot (graphics.c:915)
==2306== by 0x61F74B: eval_plots (plot2d.c:3612)
==2306== by 0x44BB88: plot_command (command.c:1897)
==2306== by 0x4411AB: command (command.c:659)
==2306== by 0x4411AB: do_line (command.c:429)
==2306== by 0x5CD14B: load_file (misc.c:335)
==2306== by 0x406416: main (plot.c:636)
==2306== Address 0x50 is not stack'd, malloc'd or (recently) free'd
==2306==
==2306==
==2306== Process terminating with default action of signal 11 (SIGSEGV)
==2306== Access not within mapped region at address 0x50
==2306== at 0x535C31: plot_points (graphics.c:2333)
==2306== by 0x55DFB7: do_plot (graphics.c:915)
==2306== by 0x61F74B: eval_plots (plot2d.c:3612)
==2306== by 0x44BB88: plot_command (command.c:1897)
==2306== by 0x4411AB: command (command.c:659)
==2306== by 0x4411AB: do_line (command.c:429)
==2306== by 0x5CD14B: load_file (misc.c:335)
==2306== by 0x406416: main (plot.c:636)
==2306== If you believe this happened as a result of a stack
==2306== overflow in your program's main thread (unlikely but
==2306== possible), you can try to increase the size of the
==2306== main thread stack using the --main-stacksize= flag.
==2306== The main thread stack size used in this run was 8388608.
==2306==
==2306== HEAP SUMMARY:
==2306== in use at exit: 35,830 bytes in 184 blocks
==2306== total heap usage: 325 allocs, 141 frees, 202,748 bytes allocated
==2306==
==2306== LEAK SUMMARY:
==2306== definitely lost: 0 bytes in 0 blocks
==2306== indirectly lost: 0 bytes in 0 blocks
==2306== possibly lost: 0 bytes in 0 blocks
==2306== still reachable: 35,830 bytes in 184 blocks
==2306== suppressed: 0 bytes in 0 blocks
==2306== Rerun with --leak-check=full to see details of leaked memory
==2306==
==2306== For lists of detected and suppressed errors, rerun with: -s
==2306== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

[Ethan Merritt]

I cannot reproduce this problem in 5.4.0 or in current 5.5

[liuchenyifan]

The version is gnuplot 5.5 (last modified in 9.18) on centos linux 7.7.1908;
I try it several times , it can be reproduce by : gnuplot bug6