On 13/10/2021 08:56, Adhemerval Zanella wrote:
> 
> 
> On 13/10/2021 08:44, Adhemerval Zanella wrote:
>>
>>
>> On 13/10/2021 07:58, Adhemerval Zanella wrote:
>>>
>>>
>>>> On 13 Oct 2021, at 06:19, Szabolcs Nagy <szabolcs.nagy@arm.com> wrote:
>>>>
>>>> The 10/13/2021 08:42, Manuel Lauss via Libc-alpha wrote:
>>>>> [resend with libc-alpha]
>>>>> Hi Adhemerval,
>>>>>
>>>>> Your recent commit 4af6982e4c9fc465ffb7a54b794aaaa134241f05 ("elf: Fix
>>>>> elf_get_dynamic_info definition")  causes a lot (but not all) of my
>>>>> applications
>>>>> to segfault:
>>>>>
>>>>> Program received signal SIGSEGV, Segmentation fault.
>>>>> _dl_fixup (l=<optimized out>, reloc_arg=<optimized out>) at dl-runtime.c:146
>>>>> 146       return elf_machine_fixup_plt (l, result, refsym, sym, reloc,
>>>>> rel_addr, value);
>>>>> (gdb) bt
>>>>> #0  _dl_fixup (l=<optimized out>, reloc_arg=<optimized out>) at dl-runtime.c:146
>>>>> #1  0x00007ffff7fe251a in _dl_runtime_resolve_xsavec () at
>>>>> ../sysdeps/x86_64/dl-trampoline.h:126
>>>>> #2  0x000055555555634e in main (argc=1, argv=0x7fffffffd568) at
>>>>> iconvconfig.c:288
>>>>>
>>>>> Reverting the commit fixes the problem. Gcc, python, etc seem to be
>>>>> not affected, while for example iconvconfig and openssh are.
>>>>
>>>> on aarch64 buildbot i see
>>>>
>>>> FAIL: nptl/test-cond-printers
>>>> FAIL: nptl/test-condattr-printers
>>>> FAIL: nptl/test-mutex-printers
>>>> FAIL: nptl/test-mutexattr-printers
>>>> FAIL: nptl/test-rwlock-printers
>>>> FAIL: nptl/test-rwlockattr-printers
>>>>
>>>> and
>>>>
>>>> $ cat nptl/test-cond-printers.out
>>>> Error: Response does not match the expected pattern.
>>>> Command: start
>>>> Expected pattern: main
>>>> Response:  Temporary breakpoint 1 at 0xac4: file test-cond-printers.c, line 36.
>>>> Starting program: /work/glibc-aarch64-linux/build/build/nptl/test-cond-printers
>>>>
>>>> Program received signal SIGSEGV, Segmentation fault.
>>>> _dl_fixup (l=<optimized out>, reloc_arg=<optimized out>) at dl-runtime.c:146
>>>> 146       return elf_machine_fixup_plt (l, result, refsym, sym, reloc, rel_addr, value);
>>>> (gdb)
>>>>
>>>>
>>>> it seems to be a bind-now pie where PLT relocs are not yet
>>>> processed when __libc_start_main is called but PLTGOT is
>>>> already marked readonly so _dl_fixup crashes.
>>>
>>> I will check this out.
>>>
>>
>> I am trying to reproduce it on aarch64-linux-gnu without much success (using
>> gcc 11.1.1 20210702 and ld 2.36.1.20210702). Neither ssh or iconvconfig fails
>> when running through the built glibc (using ubuntu 21.04 one).
>>
>> Any idea on how to reproduce it?
>>
> 
> Sigh... I think this is another fallback of RTLD_BOOTSTRAP.  I fixed the
> elf_get_dynamic_info(), but there are lot of more usage that changes
> the semantic of the nested functions (specifically on elf/do-rel.h
> and dl-machine.h).
> 
> I will try to fix, I think we should define RTLD_BOOTSTRAP before the
> fist dynamic-link.h in rtld.
> 

Could you check if the attached patch fixes it?  The rtld.c now should get
all the required function with the expected semantic (RTLD_BOOTSTRAP defined).