Silent ASAN_SIGSEGV

[pbn4]

Info: gcc-4.8.3, Ubuntu 16.04 LTS.

I compiled a project with -fsanitize=address. At startup the process freezes:

==10773== T5: stack [0x7fffd8f37000,0x7fffd9738000) size 0x801000; local=0x7fffd9736eec
==1== Parsed ASAN_OPTIONS: SHADOW_OFFSET=0x7fff0000:verbosity=1:debug=true:legacy_pthread_cond=true
==1== AddressSanitizer: libc interceptors initialized
|| `[0x10007fff8000, 0x7fffffffffff]` || HighMem    ||
|| `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
|| `[0x00008fff7000, 0x02008fff6fff]` || ShadowGap  ||
|| `[0x00007fff8000, 0x00008fff6fff]` || LowShadow  ||
|| `[0x000000000000, 0x00007fff7fff]` || LowMem     ||
MemToShadow(shadow): 0x00008fff7000 0x000091ff6dff 0x004091ff6e00 0x02008fff6fff
red_zone=16
malloc_context_size=30
SHADOW_SCALE: 3
SHADOW_GRANULARITY: 8
SHADOW_OFFSET: 7fff8000
==1== Installed the sigaction for signal 11
==1== T0: stack [0x7fffff7ff000,0x7ffffffff000) size 0x800000; local=0x7fffffffd4bc
==1== AddressSanitizer Init done
ASAN:SIGSEGV

in gdb I see that my code has hung in:

#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185

Issue #733 is somewhat similar but does not provide clear answer to the problem.

How can I experiment with shadow memory as mentioned in #733?

Turns out it was cause by a conflict between asan shadow memory and our code. We changed asan shadow memory, and it worked now.

[dvyukov]

Hi Michał,

We generally don't maintain old releases and I doubt gcc 4.8 is maintained at all as it's 3.5 years old.
Please try latest gcc or clang. It's likely the problem is already fixed there whatever it is.