Hi Daniel, Daniel Fahlgren wrote,
Hi Waldemar,
On Mon, 2015-09-14 at 06:52 +0200, Waldemar Brodkorb wrote:
...
Does this happen only when uClibc itself is compiled with stack protection? Or just when the pthread app is statically linked and compiled with -fstack-protector?
This only happen when libpthread.a is compiled with stack protection and the binary is statically linked. I have tried compiling the app both with and without -fstack-protector-all but that doesn't change the behavior. A libpthread.a not compiled with stack protection also does not show this behavior.
With uClibc 0.9.33.x the same thing happens. With glibc the program works.
I can reproduce the bug. Moving __libc_setup_tls from NPTL init to __uClibc_main.c fixes it. Why do you think it is ugly to do this?
With my patch __libc_setup_tls() was called twice. I also haven't thought it through if if is ok to simply move it from the pthread code or if something else is depending on it being there.
Does attached patch works for you? Just a cleaned up version of your fix. It doesn't produce any regressions running the testsuite.
Yes, that patch works just fine. I have tested it on my limited test case as well as in the environment where I first encountered the bug.
I still get segfaults when using __UCLIBC_HAS_SSP__ while compiling uClibc-ng and then use the results to statically link your test app with -fstack-protector-all. Gdb shows: (gdb) bt #0 0x000000000040cf1b in _dl_aux_init ()
So it seems not completely solved, yet. Any idea?
best regards Waldemar