Hi Vineet, On Tue, Oct 01, 2013 at 05:51:44PM +0530, Vineet Gupta wrote: > A simple statically linked hello world program was segfaulting for ARC > in linuxthreads.old configuration (although the root casue applies > cross-arch for NPTL as well as linuxthreads.old as described)
I haven't noticed you patch when posting mine (http://lists.busybox.net/pipermail/uclibc/2013-October/047962.html). Care to add __h_errno_location to your patch? Thanks, baruch > The crash was due to branch to NULL in _stdio_init > > 0001026c <_stdio_init>: > 1026c: push_s blink > 1026e: st.a r13,[sp,-8] > 10272: bl.d 0 --> supposed call to __errno_location > > The call was NOT getting patched to libc internal only alias > __GI___errno_location, because it was weak while it's exported cousin, > __errno_location was strong/normal. > > arc-linux-uclibc-nm libc/misc/internals/__errno_location.os > > 00000000 W __GI___errno_location > 00000000 T __errno_location > > This is exactly opposite to what is expected. > > Quoting Peter S. Mazinger, commit 87936cd013041 "errno and *_init cleanup" > > | The rule adopted: > | for enabled threads we make in libc the __GI_x() variants strong, x() weak > | and (should) provide another strong x() in libpthread. > | If threads are disabled, even the __GI_x() variants are weak. > > With the fix, we see the right settings as below > > 00000000 T __GI___errno_location > 00000000 W __errno_location > > Note that problem won't show up in a static busybox build as it references > errno and that seems to elide the issue. > > I can confirm the same/more issues with latest ARM buildroot builds w/o > my fix. > > (1). linuxthreads.old (broken just like ARC) > > arm-linux-nm uclibc-snapshot/libc/misc/internals/__errno_location.os > > 00000000 W __GI___errno_location > 00000000 T __errno_location > > But presumably the issue there is NOT catestrophic because ARM linker is > likely smarter and patches a NOP instead of NULL branch. > > 00008388 <_stdio_init>: > 8388: e92d4038 push {r3, r4, r5, lr} > 838c: e320f000 nop {0} > > (2) NPTL build (exported version is not weak) > > 00000000 T __GI___errno_location > 00000000 T __errno_location > > This causes a static link with libpthread and test program > referencing errno to fail to link. > > #include <errno.h> > int main(void) > { > printf("%d\n", errno); > } > > arm-linux-gcc -static -pthread -o tst tst.o > > > arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libc.a(__errno_location.os): > In function `__errno_location': __errno_location.c:(.text+0x0): > multiple definition of `__errno_location' > arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libpthread.a > (errno_location.os):errno_location.c:(.text+0x0): first defined > here > > Signed-off-by: Vineet Gupta <[email protected]> > --- > libc/misc/internals/__errno_location.c | 2 +- > libc/sysdeps/linux/common/bits/errno.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/libc/misc/internals/__errno_location.c > b/libc/misc/internals/__errno_location.c > index dec913f..be7a909 100644 > --- a/libc/misc/internals/__errno_location.c > +++ b/libc/misc/internals/__errno_location.c > @@ -16,4 +16,4 @@ int *__errno_location(void) > { > return &errno; > } > -libc_hidden_def(__errno_location) > +libc_hidden_weak(__errno_location) > diff --git a/libc/sysdeps/linux/common/bits/errno.h > b/libc/sysdeps/linux/common/bits/errno.h > index 7ef1b94..777338f 100644 > --- a/libc/sysdeps/linux/common/bits/errno.h > +++ b/libc/sysdeps/linux/common/bits/errno.h > @@ -43,7 +43,7 @@ > /* Function to get address of global `errno' variable. */ > extern int *__errno_location (void) __THROW __attribute__ ((__const__)); > # ifdef _LIBC > -# ifndef __UCLIBC_HAS_TLS__ > +# if !defined(__UCLIBC_HAS_TLS__) && !defined(__UCLIBC_HAS_THREADS__) > extern int weak_const_function *__errno_location(void); > # endif > # endif > -- > 1.8.1.2 -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - [email protected] - tel: +972.2.679.5364, http://www.tkos.co.il - _______________________________________________ uClibc mailing list [email protected] http://lists.busybox.net/mailman/listinfo/uclibc
