Program that segfaults with -Ofast

[Mason]

On 05/01/2018 14:09, Mason wrote:

> On 05/01/2018 12:58, Christer Solskogen wrote:
> 
>> ==7821== Conditional jump or move depends on uninitialised value(s)
>> ==7821==    at 0x29478C: read_kickstart (memory.cpp:581)
>> ==7821==    by 0x29478C: read_kickstart_version(uae_prefs*) (memory.cpp:1151)
>> ==7821==    by 0x28E243: fixup_prefs(uae_prefs*, bool) (main.cpp:195)
>> ==7821==    by 0x1AB34F: cfgfile_load(uae_prefs*, char const*, int*, int, int) (cfgfile.cpp:3969)
>> ==7821==    by 0x2F593B: target_cfgfile_load(uae_prefs*, char const*, int, int) (amiberry.cpp:527)
>> ==7821==    by 0x28F927: parse_cmdline_and_init_file (main.cpp:608)
>> ==7821==    by 0x28F927: real_main2 (main.cpp:686)
>> ==7821==    by 0x28F927: real_main(int, char**) (main.cpp:784)
>> ==7821==    by 0x151D97: main (amiberry.cpp:920)
>> ==7821==
>> ==7821== Conditional jump or move depends on uninitialised value(s)
>> ==7821==    at 0x29479C: read_kickstart (memory.cpp:584)
>> ==7821==    by 0x29479C: read_kickstart_version(uae_prefs*) (memory.cpp:1151)
>> ==7821==    by 0x28E243: fixup_prefs(uae_prefs*, bool) (main.cpp:195)
>> ==7821==    by 0x1AB34F: cfgfile_load(uae_prefs*, char const*, int*, int, int) (cfgfile.cpp:3969)
>> ==7821==    by 0x2F593B: target_cfgfile_load(uae_prefs*, char const*, int, int) (amiberry.cpp:527)
>> ==7821==    by 0x28F927: parse_cmdline_and_init_file (main.cpp:608)
>> ==7821==    by 0x28F927: real_main2 (main.cpp:686)
>> ==7821==    by 0x28F927: real_main(int, char**) (main.cpp:784)
>> ==7821==    by 0x151D97: main (amiberry.cpp:920)
>> ==7821==
>> ==7821== Invalid read of size 4
>> ==7821==    at 0x28E2AC: fixup_prefs(uae_prefs*, bool) (main.cpp:207)
>> ==7821==    by 0x1AB34F: cfgfile_load(uae_prefs*, char const*, int*, int, int) (cfgfile.cpp:3969)
>> ==7821==    by 0x2F593B: target_cfgfile_load(uae_prefs*, char const*, int, int) (amiberry.cpp:527)
>> ==7821==    by 0x28F927: parse_cmdline_and_init_file (main.cpp:608)
>> ==7821==    by 0x28F927: real_main2 (main.cpp:686)
>> ==7821==    by 0x28F927: real_main(int, char**) (main.cpp:784)
>> ==7821==    by 0x151D97: main (amiberry.cpp:920)
>> ==7821==  Address 0x29bb8 is not stack'd, malloc'd or (recently) free'd
> 
> I'm starting to think I'm not looking at the correct source code :-)

Indeed! You are using the 'dev' branch. Doh! :-)

	uae_u8 mem[32] = { 0 };
	read_kickstart(z, mem, sizeof mem, 0, 0);

So memory.cpp:1151 = read_kickstart() with a size of 32.

  oldpos = zfile_ftell (f);
  i = zfile_fread (buffer, 1, 11, f);
  if (!memcmp(buffer, "KICK", 4)) {

You should print the value of 'oldpos' and 'i' because it looks like
the fread call could not find 4 bytes to load into 'buffer'...
(The UB at memory.cpp:581 and memory.cpp:584)

You should also print f->name, f->zipname, f->size, f->seek.

Regards.