H.J. Lu 5c522d7a58 x86: Include <bits/stdlib-bsearch.h> in dl-cacheinfo.h ...

On x86-64, when glibc is configured with --enable-stack-protector=all
and compiled with -Os, ld.so crashes very early:

(gdb) r --direct
Starting program: /export/build/gnu/tools-build/glibc-gitlab/build-x86_64-linux/string/test-memswap --direct

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7f41b0a in bsearch (__key=__key@entry=0x7fffffffda28,
    __base=__base@entry=0x7ffff7fca140 <intel_02_known>,
    __nmemb=__nmemb@entry=68, __size=__size@entry=8,
    __compar=__compar@entry=0x7ffff7f3b691 <intel_02_known_compare>)
    at ../bits/stdlib-bsearch.h:22
22	{
(gdb) disass
Dump of assembler code for function bsearch:
   0x00007ffff7f41af0 <+0>:	push   %r15
   0x00007ffff7f41af2 <+2>:	mov    %rcx,%r15
   0x00007ffff7f41af5 <+5>:	push   %r14
   0x00007ffff7f41af7 <+7>:	push   %r13
   0x00007ffff7f41af9 <+9>:	mov    %rsi,%r13
   0x00007ffff7f41afc <+12>:	push   %r12
   0x00007ffff7f41afe <+14>:	mov    %rdi,%r12
   0x00007ffff7f41b01 <+17>:	push   %rbp
   0x00007ffff7f41b02 <+18>:	mov    %rdx,%rbp
   0x00007ffff7f41b05 <+21>:	push   %rbx
   0x00007ffff7f41b06 <+22>:	sub    $0x18,%rsp
=> 0x00007ffff7f41b0a <+26>:	mov    %fs:0x28,%r14
^^^^^^^^^^^^^^^^^^^^^^^^^^^^ We can't use stack protector at this point.
   0x00007ffff7f41b13 <+35>:	mov    %r14,0x8(%rsp)
   0x00007ffff7f41b18 <+40>:	mov    %r8,%r14
   0x00007ffff7f41b1b <+43>:	test   %rbp,%rbp
   0x00007ffff7f41b1e <+46>:	je     0x7ffff7f41b48 <bsearch+88>
   0x00007ffff7f41b20 <+48>:	mov    %rbp,%rbx
   0x00007ffff7f41b23 <+51>:	mov    %r12,%rdi
   0x00007ffff7f41b26 <+54>:	shr    $1,%rbx
   0x00007ffff7f41b29 <+57>:	imul   %r15,%rbx
   0x00007ffff7f41b2d <+61>:	add    %r13,%rbx
   0x00007ffff7f41b30 <+64>:	mov    %rbx,%rsi
(gdb) bt
 #0  0x00007ffff7f41b0a in bsearch (__key=__key@entry=0x7fffffffda28,
    __base=__base@entry=0x7ffff7fca140 <intel_02_known>,
    __nmemb=__nmemb@entry=68, __size=__size@entry=8,
    __compar=__compar@entry=0x7ffff7f3b691 <intel_02_known_compare>)
    at ../bits/stdlib-bsearch.h:22
 #1  0x00007ffff7f3c1be in intel_check_word (name=188, value=1979933440,
    has_level_2=has_level_2@entry=0x7fffffffda7f,
    no_level_2_or_3=no_level_2_or_3@entry=0x7fffffffda7e,
    cpu_features=<optimized out>) at ../sysdeps/x86/dl-cacheinfo.h:217
 #2  0x00007ffff7f3c29f in handle_intel (name=name@entry=188,
    cpu_features=<optimized out>) at ../sysdeps/x86/dl-cacheinfo.h:279
 #3  0x00007ffff7f3ccf9 in dl_init_cacheinfo (cpu_features=<optimized out>)
    at ../sysdeps/x86/dl-cacheinfo.h:852
 #4  init_cpu_features (cpu_features=<optimized out>)
    at ../sysdeps/x86/cpu-features.c:1153
 #5  0x00007ffff7f3d6f9 in __libc_start_main_impl (main=0x7ffff7f396dc <main>,
    argc=2, argv=0x7fffffffdbe8, init=<optimized out>, fini=<optimized out>,
    rtld_fini=0x0, stack_end=0x7fffffffdbd8) at ../csu/libc-start.c:269
 #6  0x00007ffff7f39901 in _start () at ../sysdeps/x86_64/start.S:115
(gdb)

The problem is that since __USE_EXTERN_INLINES isn't defined with -Os,
the inline bsearch in <bits/stdlib-bsearch.h> isn't available and the
external bsearch is compiled with stack protector.  Include
<bits/stdlib-bsearch.h> in dl-cacheinfo.h fixed BZ #33374.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Sam James <sam@gentoo.org>

2025-09-08 20:31:36 -07:00

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