Re: [pushed] [gdb/testsuite] Fix gdb.threads/dlopen-libpthread.exp for upstream glibc

[Tom de Vries <tdevries@suse.de>]

On 1/11/23 17:20, Simon Marchi wrote:
> 
> 
> On 1/11/23 04:17, Tom de Vries via Gdb-patches wrote:
>> On 1/10/23 19:05, Simon Marchi wrote:
>>>> Attached patch fixes things.
>>>>
>>>> WDYT?
>>>>
>>>> Thanks,
>>>> - Tom
>>>
>>>
>>> Here:
>>>
>>>> # We link the exec without -lpthread, but libpthread.so may already be loaded at main
>>>> # due to LD_PRELOAD.
>>>> set libpthread_maybe_preloaded 0
>>>> set binfile [standard_output_file $executable]
>>>> if { [has_dependency $binfile libpthread\\.so] == 1 } {
>>>>       set libpthread_maybe_preloaded 1
>>>> }
>>>
>>> Ok, so this works because ldd is influenced by LD_PRELOAD, I didn't
>>> know.
>>>
>>
>> Yes, while lddtree is not, which had me confused for a while.
>>
>>>>
>>>> # We link the shlib with -lpthread, but since glibc 2.34 libpthread has been
>>>> # merged with libc, so libpthread.so may not be a dependency.
>>>> set libpthread_missing 0
>>>> if { [has_dependency $binfile libpthread\\.so] == 0 } {
>>>>       set libpthread_missing 1
>>>> }
>>>
>>> The two has_dependency calls use $binfile.  Should one of them use
>>> $binfile_lib?  The second one I think.
>>
>> Yes, thanks for catching this.
>>
>> I'll commit after another build & test cycle.
> 
> Hmm, I still see the failure.  I think the second has_dependency doesn't
> work.  It returns 1 when it shouldn't, because of the
> dlopen-libpthread.so.d line:
> 
>      output of ldd /home/smarchi/build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/dlopen-libpthread/dlopen-libpthread.so is
>              linux-vdso.so.1 (0x00007ffc809ee000)^M
>              libc.so.6 => /home/smarchi/build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/dlopen-libpthread/dlopen-libpthread.so.d/libc.so.6 (0x00007f0a5cf03000)^M
>              /lib64/ld-linux-x86-64.so.2 (0x00007f0a5d132000)^M
> 
> This directory is created by build_executable_own_libs in
> lib/prelink-support.exp (used by the test).
> 
> Tweaking the regexp to include a forward slash makes it work for me:
> 

Hi Simon,

thanks for letting me know, and sorry for this ongoing annoyance.

I tested it this morning on three data points (openSUSE Leap 15.4, 
Ubuntu 22.04 with and without LD_PRELOAD=), and all looked fine.

But after you mentioned the FAIL, I did a clean build from trunk and 
managed to reproduce it.  I'm not sure what went wrong, either I tested 
the wrong test-case or I tested a different version of the patch.

Anyway, your suggestion fixes the FAIL for me as well.

I'll commit this asap.

Thanks,
- Tom

>    diff --git a/gdb/testsuite/gdb.threads/dlopen-libpthread.exp b/gdb/testsuite/gdb.threads/dlopen-libpthread.exp
>    index 134265ff470..c97e0284475 100644
>    --- a/gdb/testsuite/gdb.threads/dlopen-libpthread.exp
>    +++ b/gdb/testsuite/gdb.threads/dlopen-libpthread.exp
>    @@ -68,14 +68,14 @@ if { !$have_probe } {
>     # due to LD_PRELOAD.
>     set libpthread_maybe_preloaded 0
>     set binfile [standard_output_file $executable]
>    -if { [has_dependency $binfile libpthread\\.so] == 1 } {
>    +if { [has_dependency $binfile /libpthread\\.so] == 1 } {
>         set libpthread_maybe_preloaded 1
>     }
> 
>     # We link the shlib with -lpthread, but since glibc 2.34 libpthread has been
>     # merged with libc, so libpthread.so may not be a dependency.
>     set libpthread_missing 0
>    -if { [has_dependency $binfile_lib libpthread\\.so] == 0 } {
>    +if { [has_dependency $binfile_lib /libpthread\\.so] == 0 } {
>         set libpthread_missing 1
>     }
> 
> Simon