[Bug other/60681] New: Libbacktrace library doesn't work with QEMU in application mode

chefmax at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Thu Mar 27 07:54:00 GMT 2014


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60681

            Bug ID: 60681
           Summary: Libbacktrace library doesn't work with QEMU in
                    application mode
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: chefmax at gcc dot gnu.org
                CC: v.garbuzov at samsung dot com, y.gribov at samsung dot com

The libbacktrace library doesn't work well with QEMU in application mode.

$ arm-linux-gnueabi-gcc -fsanitize=address -g
gcc/testsuite/c-c++-common/asan/null-deref-1.c $ qemu-arm -cpu cortex-a15 -L
/home/max/install/gcc-upstream-arm/arm-linux-gnueabi/sys-root/ -R 0 -E
LD_LIBRARY_PATH=/home/max/install/gcc-upstream-arm/arm-linux-gnueabi/lib/
./a.out
...
  #0 0x873f (/home/max/build/gcc-upstream-arm/a.out+0x873f)   #1 0x876f
(/home/max/build/gcc-upstream-arm/a.out+0x876f)   #2 0x40ddb507
(/lib/libc.so.6+0x18507)

When running the same binary on the target board, libbacktrace works well:

-sh-4.1$ ./a.out
...
  #0 0x873f in NullDeref /home/m.ostapenko/null-deref-1.c:10   #1 0x876f in
main /home/m.ostapenko/null-deref-1.c:15   #2 0xb6855507 in __libc_start_main
/home/max/build.arm.cortex-a15/sources/glibc/libc/csu/libc-start.c:269

After investigation I discovered that libbacktrace scans /proc/self/exe to init
symbolizer and in QEMU case it finds information about qemu-arm binary itself,
not a.out.

Is it a real bug or we should leave this as it is now? Perhaps I should report
this to QEMU developers?



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