Bug 396476

Created attachment 113918 [details]
A test program

Here is a tiny program:

https://github.com/hjl-tools/simple-linux/tree/divide-by-zero

Valgrind can't read its DWARF debug info with zero-size PT_LOAD segment:

[hjl@gnu-cfl-1 simple-linux]$ make LD=ld.gold
gcc -g -O0   -c -o test.o test.c
test.c: In function \u2018main\u2019:
test.c:22:9: warning: division by zero [-Wdiv-by-zero]
   i = 7 / 0;
         ^
gcc -g   -c -o start.o start.S
gcc -g   -c -o syscall.o syscall.S
ld.gold  -o test test.o start.o syscall.o
./test hello world
a
make: *** [Makefile:12: all] Floating point exception
[hjl@gnu-cfl-1 simple-linux]$ valgrind ./test
==27555== Memcheck, a memory error detector
==27555== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==27555== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==27555== Command: ./test
==27555== 
a
==27555== 
==27555== Process terminating with default action of signal 8 (SIGFPE)
==27555==  Integer divide by zero at address 0x1002B95532
==27555==    at 0x40015E: ??? (in /export/ssd/git/github/simple-linux/test)
==27555==    by 0x4001A8: ??? (in /export/ssd/git/github/simple-linux/test)
==27555== 
==27555== HEAP SUMMARY:
==27555==     in use at exit: 0 bytes in 0 blocks
==27555==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==27555== 
==27555== All heap blocks were freed -- no leaks are possible
==27555== 
==27555== For counts of detected and suppressed errors, rerun with: -v
==27555== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
Floating point exception
[hjl@gnu-cfl-1 simple-linux]$ gdb test
GNU gdb (GDB) Fedora 8.1-19.fc28
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from test...done.
(gdb) r
Starting program: /export/ssd/git/github/simple-linux/test 
a

Program received signal SIGFPE, Arithmetic exception.
0x000000000040015c in main (argc=1, argv=0x7fffffffd708) at test.c:22
22	  i = 7 / 0;
(gdb)

[hjl@gnu-cfl-1 simple-linux]$ readelf -lW test

Elf file type is EXEC (Executable file)
Entry point 0x40019a
There are 3 program headers, starting at offset 64

Program Headers:
  Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
  LOAD           0x000000 0x0000000000400000 0x0000000000400000 0x000240 0x000240 R E 0x1000
  LOAD           0x001000 0x0000000000401000 0x0000000000401000 0x000000 0x000000 RW  0x1000
  GNU_STACK      0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RWE 0x10

 Section to Segment mapping:
  Segment Sections...
   00     .text .rodata .eh_frame 
   01     .data .bss 
   02     
[hjl@gnu-cfl-1 simple-linux]$