https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81939
--- Comment #4 from Vittorio Zecca <zeccav at gmail dot com> --- Dominique, this should be the same traceback as yours but with line numbers: ================================================================= ==21064==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x612000000177 at pc 0x2ad13bcaa549 bp 0x7ffeba105280 sp 0x7ffeba105278 WRITE of size 1 at 0x612000000177 thread T0 #0 0x2ad13bcaa548 in build_float_string ../../../gcc/libgfortran/io/write_float.def:665 #1 0x2ad13bcafcc6 in get_float_string ../../../gcc/libgfortran/io/write_float.def:1068 #2 0x2ad13bcbcd9b in write_float_0 ../../../gcc/libgfortran/io/write.c:1596 #3 0x2ad13bcbcfc3 in _gfortrani_write_f ../../../gcc/libgfortran/io/write.c:1623 #4 0x2ad13bc73af3 in formatted_transfer_scalar_write ../../../gcc/libgfortran/io/transfer.c:2041 #5 0x2ad13bc77902 in formatted_transfer ../../../gcc/libgfortran/io/transfer.c:2279 #6 0x2ad13bc77b86 in _gfortran_transfer_real ../../../gcc/libgfortran/io/transfer.c:2310 #7 0x2ad13bc77bb4 in _gfortran_transfer_real_write ../../../gcc/libgfortran/io/transfer.c:2316 #8 0x40094a in MAIN__ (/home/vitti/1tb/vitti/f95/a.out+0x40094a) #9 0x400ad5 in main (/home/vitti/1tb/vitti/f95/a.out+0x400ad5) #10 0x2ad13e579509 in __libc_start_main (/usr/lib64/libc.so.6+0x20509) #11 0x400729 in _start (/home/vitti/1tb/vitti/f95/a.out+0x400729) 0x612000000177 is located 0 bytes to the right of 311-byte region [0x612000000040,0x612000000177) allocated by thread T0 here: #0 0x2ad13897680a in __interceptor_malloc ../../../../gcc/libsanitizer/asan/asan_malloc_linux.cc:62 #1 0x2ad13aec9b2b in _gfortrani_xmalloc ../../../gcc/libgfortran/runtime/memory.c:42 #2 0x2ad13bcbc9f6 in select_string ../../../gcc/libgfortran/io/write.c:1557 #3 0x2ad13bcbccdf in write_float_0 ../../../gcc/libgfortran/io/write.c:1592 #4 0x2ad13bcbcfc3 in _gfortrani_write_f ../../../gcc/libgfortran/io/write.c:1623 #5 0x2ad13bc73af3 in formatted_transfer_scalar_write ../../../gcc/libgfortran/io/transfer.c:2041 #6 0x2ad13bc77902 in formatted_transfer ../../../gcc/libgfortran/io/transfer.c:2279 #7 0x2ad13bc77b86 in _gfortran_transfer_real ../../../gcc/libgfortran/io/transfer.c:2310 #8 0x2ad13bc77bb4 in _gfortran_transfer_real_write ../../../gcc/libgfortran/io/transfer.c:2316 #9 0x40094a in MAIN__ (/home/vitti/1tb/vitti/f95/a.out+0x40094a) #10 0x400ad5 in main (/home/vitti/1tb/vitti/f95/a.out+0x400ad5) #11 0x2ad13e579509 in __libc_start_main (/usr/lib64/libc.so.6+0x20509) SUMMARY: AddressSanitizer: heap-buffer-overflow ../../../gcc/libgfortran/io/write_float.def:665 in build_float_string Shadow bytes around the buggy address: 0x0c247fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c247fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c247fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c247fff8000: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00 0x0c247fff8010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 =>0x0c247fff8020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00[07]fa 0x0c247fff8030: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00 0x0c247fff8040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0c247fff8050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fa 0x0c247fff8060: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c247fff8070: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb ==21064==ABORTING