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Make sure that calloc is called at least once
PLT relocations aren't required when -z now used. Linker on master with:
commit 25070364b0ce33eed46aa5d78ebebbec6accec7e
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Sat May 16 07:00:21 2015 -0700
Don't generate PLT relocations for now binding
There is no need for PLT relocations with -z now. We can use GOT
relocations, which take less space, instead and replace 16-byte .plt
entres with 8-byte .plt.got entries.
bfd/
* elf32-i386.c (elf_i386_check_relocs): Create .plt.got section
for now binding.
(elf_i386_allocate_dynrelocs): Use .plt.got section for now
binding.
* elf64-x86-64.c (elf_x86_64_check_relocs): Create .plt.got
section for now binding.
(elf_x86_64_allocate_dynrelocs): Use .plt.got section for now
binding.
won't generate PLT relocations with -z now. elf/tst-audit2.c expect
certain order of execution in ld.so. With PLT relocations, the GOTPLT
entry of calloc is update to calloc defined in tst-audit2:
(gdb) bt
skip_ifunc=<optimized out>, reloc_addr_arg=<optimized out>,
version=<optimized out>, sym=<optimized out>, map=<optimized out>)
at ../sysdeps/i386/dl-machine.h:329
out>,
nrelative=<optimized out>, relsize=<optimized out>,
reladdr=<optimized out>, map=<optimized out>) at do-rel.h:137
reloc_mode=reloc_mode@entry=0,
consider_profiling=1, consider_profiling@entry=0) at dl-reloc.c:258
user_entry=0xffffcf1c, auxv=0xffffd0a8) at rtld.c:2133
start_argptr=start_argptr@entry=0xffffcfb0,
dl_main=dl_main@entry=0xf7fda6f0 <dl_main>) at
../elf/dl-sysdep.c:249
from /export/build/gnu/glibc-32bit/build-i686-linux/elf/ld.so
(gdb)
and then calloc is called:
(gdb) c
Continuing.
Breakpoint 4, calloc (n=n@entry=20, m=4) at tst-audit2.c:18
18 {
(gdb) bt
reloc_mode=reloc_mode@entry=0, consider_profiling=1,
consider_profiling@entry=0) at dl-reloc.c:272
user_entry=0xffffcf1c, auxv=0xffffd0a8) at rtld.c:2133
start_argptr=start_argptr@entry=0xffffcfb0,
dl_main=dl_main@entry=0xf7fda6f0 <dl_main>) at
../elf/dl-sysdep.c:249
from /export/build/gnu/glibc-32bit/build-i686-linux/elf/ld.so
(gdb)
With GOT relocation, calloc in ld.so is called first:
(gdb) bt
consider_profiling=1) at dl-reloc.c:272
user_entry=0xffffcf0c, auxv=0xffffd098) at rtld.c:2074
start_argptr=start_argptr@entry=0xffffcfa0,
dl_main=dl_main@entry=0xf7fda6c0 <dl_main>) at
../elf/dl-sysdep.c:249
from /export/build/gnu/glibc-32bit-test/build-i686-linux/elf/ld.so
(gdb)
and then the GOT entry of calloc is updated:
(gdb) bt
skip_ifunc=<optimized out>, reloc_addr_arg=<optimized out>,
version=<optimized out>, sym=<optimized out>, map=<optimized out>)
at ../sysdeps/i386/dl-machine.h:329
out>,
nrelative=<optimized out>, relsize=<optimized out>,
reladdr=<optimized out>, map=<optimized out>) at do-rel.h:137
reloc_mode=reloc_mode@entry=0,
consider_profiling=1, consider_profiling@entry=0) at dl-reloc.c:258
user_entry=0xffffcf0c, auxv=0xffffd098) at rtld.c:2133
start_argptr=start_argptr@entry=0xffffcfa0,
dl_main=dl_main@entry=0xf7fda6c0 <dl_main>) at
../elf/dl-sysdep.c:249
from /export/build/gnu/glibc-32bit-test/build-i686-linux/elf/ld.so
(gdb)
After that, since calloc isn't called from ld.so nor any other modules,
magic in tst-audit2 isn't updated. Both orders are correct. This patch
makes sure that calloc in tst-audit2.c is called at least once from ld.so.
[BZ #18422]
* Makefile ($(objpfx)tst-audit2): Depend on $(libdl).
($(objpfx)tst-audit2.out): Also depend on
$(objpfx)tst-auditmod9b.so.
* elf/tst-audit2.c: Include <dlfcn.h>.
(calloc_called): New.
(calloc): Allow to be called more than once.
(do_test): dllopen/dlclose $ORIGIN/tst-auditmod9b.so.
This commit is contained in:
H.J. Lu
parent
be2e25bbd7
commit
58007e9e68
11
ChangeLog
11
ChangeLog
@ -1,3 +1,14 @@
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2015-05-28 H.J. Lu <hongjiu.lu@intel.com>
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[BZ #18422]
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* Makefile ($(objpfx)tst-audit2): Depend on $(libdl).
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($(objpfx)tst-audit2.out): Also depend on
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$(objpfx)tst-auditmod9b.so.
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* elf/tst-audit2.c: Include <dlfcn.h>.
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(calloc_called): New.
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(calloc): Allow to be called more than once.
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(do_test): dllopen/dlclose $ORIGIN/tst-auditmod9b.so.
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2015-05-28 Wilco Dijkstra <wdijkstr@arm.com>
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* sysdeps/ieee754/dbl-64/s_fabs.c: (__fabs): Call __builtin_fabs.
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2
NEWS
2
NEWS
@ -19,7 +19,7 @@ Version 2.22
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18047, 18049, 18068, 18080, 18093, 18100, 18104, 18110, 18111, 18125,
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18128, 18138, 18185, 18196, 18197, 18206, 18210, 18211, 18217, 18220,
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18221, 18234, 18244, 18247, 18287, 18319, 18333, 18346, 18397, 18409,
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18410, 18412, 18418, 18434, 18444.
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18410, 18412, 18418, 18422, 18434, 18444.
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* Cache information can be queried via sysconf() function on s390 e.g. with
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_SC_LEVEL1_ICACHE_SIZE as argument.
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@ -1034,7 +1034,8 @@ $(objpfx)tst-dlmopen3.out: $(objpfx)tst-dlmopen1mod.so
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$(objpfx)tst-audit1.out: $(objpfx)tst-auditmod1.so
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tst-audit1-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so
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$(objpfx)tst-audit2.out: $(objpfx)tst-auditmod1.so
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$(objpfx)tst-audit2: $(libdl)
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$(objpfx)tst-audit2.out: $(objpfx)tst-auditmod1.so $(objpfx)tst-auditmod9b.so
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# Prevent GCC-5 from translating a malloc/memset pair into calloc
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CFLAGS-tst-audit2.c += -fno-builtin
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tst-audit2-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so
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@ -3,26 +3,35 @@
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <dlfcn.h>
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#define MAGIC1 0xabcdef72
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#define MAGIC2 0xd8675309
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static __thread unsigned int magic[] = { MAGIC1, MAGIC2 };
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static __thread int calloc_called;
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#undef calloc
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/* This calloc definition will be called by the dynamic linker itself.
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We test that it has initialized our TLS block by the time it does so. */
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We test that interposed calloc is called by the dynamic loader, and
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that TLS is fully initialized by then. */
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void *
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calloc (size_t n, size_t m)
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{
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if (magic[0] != MAGIC1 || magic[1] != MAGIC2)
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if (!calloc_called)
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{
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printf ("{%x, %x} != {%x, %x}\n", magic[0], magic[1], MAGIC1, MAGIC2);
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abort ();
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/* Allow our calloc to be called more than once. */
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calloc_called = 1;
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if (magic[0] != MAGIC1 || magic[1] != MAGIC2)
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{
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printf ("{%x, %x} != {%x, %x}\n",
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magic[0], magic[1], MAGIC1, MAGIC2);
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abort ();
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}
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magic[0] = MAGIC2;
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magic[1] = MAGIC1;
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}
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magic[0] = MAGIC2;
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magic[1] = MAGIC1;
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n *= m;
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void *ptr = malloc (n);
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@ -34,6 +43,11 @@ calloc (size_t n, size_t m)
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static int
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do_test (void)
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{
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/* Make sure that our calloc is called from the dynamic linker at least
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once. */
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void *h = dlopen("$ORIGIN/tst-auditmod9b.so", RTLD_LAZY);
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if (h != NULL)
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dlclose (h);
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if (magic[1] != MAGIC1 || magic[0] != MAGIC2)
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{
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printf ("{%x, %x} != {%x, %x}\n", magic[0], magic[1], MAGIC2, MAGIC1);
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