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ifuncmain6pie: Remove the circular IFUNC dependency [BZ #20019]

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On x86, ifuncmain6pie failed with:

[hjl@gnu-cfl-2 build-i686-linux]$ ./elf/ifuncmain6pie --direct
./elf/ifuncmain6pie: IFUNC symbol 'foo' referenced in '/export/build/gnu/tools-build/glibc-32bit/build-i686-linux/elf/ifuncmod6.so' is defined in the executable and creates an unsatisfiable circular dependency.
[hjl@gnu-cfl-2 build-i686-linux]$ readelf -rW elf/ifuncmod6.so | grep foo
00003ff4  00000706 R_386_GLOB_DAT         0000400c   foo_ptr
00003ff8  00000406 R_386_GLOB_DAT         00000000   foo
0000400c  00000401 R_386_32               00000000   foo
[hjl@gnu-cfl-2 build-i686-linux]$

Remove non-JUMP_SLOT relocations against foo in ifuncmod6.so, which
trigger the circular IFUNC dependency, and build ifuncmain6pie with
-Wl,-z,lazy.
This commit is contained in:
H.J. Lu 2021-01-04 14:25:39 -08:00
parent cf12900645
commit 7137d682eb
3 changed files with 9 additions and 15 deletions
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2
elf/Makefile
View File

@ -1403,6 +1403,8 @@ CFLAGS-ifuncmain7pie.c += $(pie-ccflag)
CFLAGS-ifuncmain9pie.c += $(pie-ccflag) CFLAGS-ifuncmain9pie.c += $(pie-ccflag)
CFLAGS-tst-ifunc-textrel.c += $(pic-ccflag) CFLAGS-tst-ifunc-textrel.c += $(pic-ccflag)
LDFLAGS-ifuncmain6pie = -Wl,-z,lazy
$(objpfx)ifuncmain1pie: $(objpfx)ifuncmod1.so $(objpfx)ifuncmain1pie: $(objpfx)ifuncmod1.so
$(objpfx)ifuncmain1staticpie: $(objpfx)ifuncdep1pic.o $(objpfx)ifuncmain1staticpie: $(objpfx)ifuncdep1pic.o
$(objpfx)ifuncmain1vispie: $(objpfx)ifuncmod1.so $(objpfx)ifuncmain1vispie: $(objpfx)ifuncmod1.so

14
elf/ifuncmain6pie.c
View File

@ -9,7 +9,6 @@
#include "ifunc-sel.h" #include "ifunc-sel.h"
typedef int (*foo_p) (void); typedef int (*foo_p) (void);
extern foo_p foo_ptr;
static int static int
one (void) one (void)
@ -28,20 +27,17 @@ foo_ifunc (void)
} }
extern int foo (void); extern int foo (void);
extern foo_p get_foo (void); extern int call_foo (void);
extern foo_p get_foo_p (void); extern foo_p get_foo_p (void);
foo_p my_foo_ptr = foo; foo_p foo_ptr = foo;
int int
main (void) main (void)
{ {
foo_p p; foo_p p;
p = get_foo (); if (call_foo () != -30)
if (p != foo)
abort ();
if ((*p) () != -30)
abort (); abort ();
p = get_foo_p (); p = get_foo_p ();
@ -52,12 +48,8 @@ main (void)
if (foo_ptr != foo) if (foo_ptr != foo)
abort (); abort ();
if (my_foo_ptr != foo)
abort ();
if ((*foo_ptr) () != -30) if ((*foo_ptr) () != -30)
abort (); abort ();
if ((*my_foo_ptr) () != -30)
abort ();
if (foo () != -30) if (foo () != -30)
abort (); abort ();

8
elf/ifuncmod6.c
View File

@ -4,7 +4,7 @@ extern int foo (void);
typedef int (*foo_p) (void); typedef int (*foo_p) (void);
foo_p foo_ptr = foo; extern foo_p foo_ptr;
foo_p foo_p
get_foo_p (void) get_foo_p (void)
@ -12,8 +12,8 @@ get_foo_p (void)
return foo_ptr; return foo_ptr;
} }
foo_p int
get_foo (void) call_foo (void)
{ {
return foo; return foo ();
} }