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* [Bug libc/13618] New: elf_machine_rela may call unrelocated address while resolving IFUNC
@ 2012-01-23 20:24 ppluzhnikov at google dot com
  2012-01-24 12:21 ` [Bug libc/13618] " aj at suse dot de
                   ` (14 more replies)
  0 siblings, 15 replies; 16+ messages in thread
From: ppluzhnikov at google dot com @ 2012-01-23 20:24 UTC (permalink / raw)
  To: glibc-bugs

http://sourceware.org/bugzilla/show_bug.cgi?id=13618

             Bug #: 13618
           Summary: elf_machine_rela may call unrelocated address while
                    resolving IFUNC
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper.fsp@gmail.com
        ReportedBy: ppluzhnikov@google.com
    Classification: Unclassified


The test is reduced from
https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/919202

Reproduces with current git trunk.

// foo.c
#include <math.h>
int foo (double d) { return floor (d) != 0; }

// bar.c
int bar () { return foo (); }

// main.c
#include <dlfcn.h>
#include <stdio.h>

int
main (int argc, char *argv[])
{
  const char *lib = "./bar.so";
  if (argc > 1) lib = argv[1];
  void *h = dlopen (lib, RTLD_NOW);  // RTLD_LAZY -> no bug
  if (h == 0)
    {
      puts (dlerror ());
      return 1;
    }
  return 0;
}

gcc -fPIC -shared -fno-builtin -o foo.so foo.c -lm &&
gcc -fPIC -shared -o bar.so -Wl,--no-as-needed -lm ./foo.so bar.c &&
gcc -g main.c -ldl

gdb -q ./a.out

Program received signal SIGSEGV, Segmentation fault.
0x0000000000005446 in ?? ()
(gdb) bt
#0  0x0000000000005446 in ?? ()
#1  0x00007ffff7351005 in floor () at
../sysdeps/x86_64/fpu/multiarch/s_floor.S:26
#2  0x00007ffff7de738f in elf_machine_rela (sym=0x7ffff7338c88,
skip_ifunc=<optimized out>, reloc_addr_arg=0x7ffff7336008, version=<optimized
out>, map=0x602af0, 
    reloc=<optimized out>) at ../sysdeps/x86_64/dl-machine.h:302
#3  elf_dynamic_do_Rela (skip_ifunc=<optimized out>, lazy=<optimized out>,
nrelative=<optimized out>, relsize=<optimized out>, reladdr=<optimized out>,
map=0x602af0)
    at do-rel.h:146
#4  _dl_relocate_object (scope=0x602e48, reloc_mode=<optimized out>,
consider_profiling=0) at dl-reloc.c:265
#5  0x00007ffff7deda23 in dl_open_worker (a=0x7fffffffd400) at dl-open.c:338
#6  0x00007ffff7de9686 in _dl_catch_error (objname=0x7fffffffd3f0,
errstring=0x7fffffffd3f8, mallocedp=0x7fffffffd3ef, operate=0x7ffff7ded7c0
<dl_open_worker>, 
    args=0x7fffffffd400) at dl-error.c:178
#7  0x00007ffff7ded36c in _dl_open (file=0x40080c "./bar.so", mode=-2147483646,
caller_dlopen=<optimized out>, nsid=-2, argc=1, argv=0x7fffffffd748,
env=0x7fffffffd758)
    at dl-open.c:575
#8  0x00007ffff7bd7f26 in dlopen_doit (a=0x7fffffffd610) at dlopen.c:67
#9  0x00007ffff7de9686 in _dl_catch_error (objname=0x7ffff7dda0d0,
errstring=0x7ffff7dda0d8, mallocedp=0x7ffff7dda0c8, operate=0x7ffff7bd7ec0
<dlopen_doit>, args=0x7fffffffd610)
    at dl-error.c:178
#10 0x00007ffff7bd84dc in _dlerror_run (operate=0x7ffff7bd7ec0 <dlopen_doit>,
args=0x7fffffffd610) at dlerror.c:164
#11 0x00007ffff7bd7fc1 in __dlopen (file=<optimized out>, mode=<optimized out>)
at dlopen.c:88
#12 0x00000000004006f1 in main (argc=1, argv=0x7fffffffd748) at main.c:8

What appears to be happening is that __floor (IFUNC) jumps to *unrelocated*
GOT entry for __get_cpu_features.

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^ permalink raw reply	[flat|nested] 16+ messages in thread
end of thread, other threads:[~2014-06-13 14:05 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-01-23 20:24 [Bug libc/13618] New: elf_machine_rela may call unrelocated address while resolving IFUNC ppluzhnikov at google dot com
2012-01-24 12:21 ` [Bug libc/13618] " aj at suse dot de
2012-01-24 12:21 ` aj at suse dot de
2012-01-24 12:22 ` idoenmez at suse dot de
2012-01-24 12:23 ` allan at archlinux dot org
2012-01-24 17:59 ` vapier at gentoo dot org
2012-01-27  2:03 ` law at redhat dot com
2012-01-27 20:06 ` drepper.fsp at gmail dot com
2012-01-27 21:05 ` vapier at gentoo dot org
2012-01-31  3:50 ` ppluzhnikov at google dot com
2012-05-23  3:22 ` ppluzhnikov at google dot com
2012-05-23  3:23 ` ppluzhnikov at google dot com
2014-02-16 16:56 ` jackie.rosen at hushmail dot com
2014-02-16 16:57 ` ismail at donmez dot ws
2014-05-28 19:43 ` schwab at sourceware dot org
2014-06-13 14:05 ` fweimer at redhat dot com

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