Bug 5174

.config please? Anything different with -O0?

Created attachment 4328 [details]
Buildroot's .config

(In reply to comment #1)
> .config please? Anything different with -O0?

The -O0 option means not -fomit-frame-pointer, so it works as expected.

Did anyone manage to reproduce the problem or am I the only one?

(In reply to comment #4)
> Did anyone manage to reproduce the problem or am I the only one?

Can you provide a gdb "bt f" with debug symbols turned on in the build, please?

PS: I ment uClibc .config, not buildroot's config.
PPS: sounds like a dup of #259

Created attachment 4346 [details]
uClibc's .config

(In reply to comment #5)
> (In reply to comment #4)
> > Did anyone manage to reproduce the problem or am I the only one?
> 
> Can you provide a gdb "bt f" with debug symbols turned on in the build, please?

I'm having a hard time compiling buildroot with debug options.  If I activate DODEBUG, DOASSERTS, SUPPORT_LD_DEBUG and SUPPORT_LD_DEBUG_EARLY in uClibc's configuration, I get the following error:

/opt/users/ig/code/buildroot-git/output/host/usr/bin/arm-unknown-linux-uclibcgnueabi-gcc -Wl,-EL -shared -Wl,--warn-common -Wl,--warn-once -Wl,-z,combreloc -Wl,-z,relro -Wl,-z,now -Wl,-z,defs   -Wl,-init,__uClibc_init  -Wl,-soname=libc.so.0 -nostdlib -o lib/libuClibc-0.9.34-git.so  -Wl,--whole-archive libc/libc_so.a -Wl,--no-whole-archive ./lib/interp.os ./lib/ld-uClibc.so.0 ./lib/uclibc_nonshared.a /opt/users/ig/code/buildroot-git/output/host/usr/lib/gcc/arm-unknown-linux-uclibcgnueabi/4.7.0/libgcc.a 
libc/libc_so.a(lockf.os): In function `__GI_lockf':
/opt/users/ig/code/buildroot-git/output/toolchain/uClibc/libc/misc/file/lockf.c:73: undefined reference to `_Unwind_Resume'
libc/libc_so.a(lockf.os):(.ARM.extab+0x0): undefined reference to `__gcc_personality_v0'
collect2: error: ld returned 1 exit status

Nevertheless, I'm able to compile with debug in Buildroot's configuration only.  Here's the backtrace:

Program received signal SIGABRT, Aborted.
0x4091daf8 in raise ()
   from /opt/users/ig/code/buildroot-git/output/target/lib/libc.so.0
(gdb) bt
#0  0x4091daf8 in raise ()
   from /opt/users/ig/code/buildroot-git/output/target/lib/libc.so.0
#1  0x40918ca0 in abort ()
   from /opt/users/ig/code/buildroot-git/output/target/lib/libc.so.0
#2  0x408d976c in unwind_phase2 (ucbp=0x11178, vrs=0x4092c1c4)
    at /opt/users/ig/code/buildroot-git/output/toolchain/gcc-4.7.0/libgcc/unwind-arm-common.inc:289
#3  0x408d98e8 in __gnu_Unwind_Resume (ucbp=0x11178, entry_vrs=0x40800054)
    at /opt/users/ig/code/buildroot-git/output/toolchain/gcc-4.7.0/libgcc/unwind-arm-common.inc:502
#4  0x408da384 in ___Unwind_Resume ()
    at /opt/users/ig/code/buildroot-git/output/toolchain/gcc-4.7.0/libgcc/config/arm/libunwind.S:345
#5  0x4080ef74 in ?? ()
   from /opt/users/ig/code/buildroot-git/output/target/lib/ld-uClibc.so.0
#6  0x4080ef74 in ?? ()
   from /opt/users/ig/code/buildroot-git/output/target/lib/ld-uClibc.so.0
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

(In reply to comment #7)
> (In reply to comment #5)
> > (In reply to comment #4)
> > > Did anyone manage to reproduce the problem or am I the only one?
> > 
> > Can you provide a gdb "bt f" with debug symbols turned on in the build, please?
> 
> I'm having a hard time compiling buildroot with debug options.  If I activate
> DODEBUG, DOASSERTS, SUPPORT_LD_DEBUG and SUPPORT_LD_DEBUG_EARLY in uClibc's
> configuration, I get the following error:
> 
> /opt/users/ig/code/buildroot-git/output/host/usr/bin/arm-unknown-linux-uclibcgnueabi-gcc
> -Wl,-EL -shared -Wl,--warn-common -Wl,--warn-once -Wl,-z,combreloc -Wl,-z,relro
> -Wl,-z,now -Wl,-z,defs   -Wl,-init,__uClibc_init  -Wl,-soname=libc.so.0
> -nostdlib -o lib/libuClibc-0.9.34-git.so  -Wl,--whole-archive libc/libc_so.a
> -Wl,--no-whole-archive ./lib/interp.os ./lib/ld-uClibc.so.0
> ./lib/uclibc_nonshared.a
> /opt/users/ig/code/buildroot-git/output/host/usr/lib/gcc/arm-unknown-linux-uclibcgnueabi/4.7.0/libgcc.a 
> libc/libc_so.a(lockf.os): In function `__GI_lockf':
> /opt/users/ig/code/buildroot-git/output/toolchain/uClibc/libc/misc/file/lockf.c:73:
> undefined reference to `_Unwind_Resume'
> libc/libc_so.a(lockf.os):(.ARM.extab+0x0): undefined reference to
> `__gcc_personality_v0'
> collect2: error: ld returned 1 exit status

This GCC bug was fixed already.
See http://gcc.gnu.org/PR51117

> 
> Nevertheless, I'm able to compile with debug in Buildroot's configuration only.
>  Here's the backtrace:
> 
> Program received signal SIGABRT, Aborted.
> 0x4091daf8 in raise ()
>    from /opt/users/ig/code/buildroot-git/output/target/lib/libc.so.0
> (gdb) bt
> #0  0x4091daf8 in raise ()
>    from /opt/users/ig/code/buildroot-git/output/target/lib/libc.so.0
> #1  0x40918ca0 in abort ()
>    from /opt/users/ig/code/buildroot-git/output/target/lib/libc.so.0
> #2  0x408d976c in unwind_phase2 (ucbp=0x11178, vrs=0x4092c1c4)
>     at
> /opt/users/ig/code/buildroot-git/output/toolchain/gcc-4.7.0/libgcc/unwind-arm-common.inc:289
> #3  0x408d98e8 in __gnu_Unwind_Resume (ucbp=0x11178, entry_vrs=0x40800054)
>     at
> /opt/users/ig/code/buildroot-git/output/toolchain/gcc-4.7.0/libgcc/unwind-arm-common.inc:502
> #4  0x408da384 in ___Unwind_Resume ()
>     at
> /opt/users/ig/code/buildroot-git/output/toolchain/gcc-4.7.0/libgcc/config/arm/libunwind.S:345
> #5  0x4080ef74 in ?? ()
>    from /opt/users/ig/code/buildroot-git/output/target/lib/ld-uClibc.so.0
> #6  0x4080ef74 in ?? ()
>    from /opt/users/ig/code/buildroot-git/output/target/lib/ld-uClibc.so.0
> Backtrace stopped: previous frame identical to this frame (corrupt stack?)

(In reply to comment #8)
> (In reply to comment #7)
> > (In reply to comment #5)
> > 
> > I'm having a hard time compiling buildroot with debug options.  If I activate
> > DODEBUG, DOASSERTS, SUPPORT_LD_DEBUG and SUPPORT_LD_DEBUG_EARLY in uClibc's
> > configuration, I get the following error:
> > 
> > /opt/users/ig/code/buildroot-git/output/host/usr/bin/arm-unknown-linux-uclibcgnueabi-gcc
> > -Wl,-EL -shared -Wl,--warn-common -Wl,--warn-once -Wl,-z,combreloc -Wl,-z,relro
> > -Wl,-z,now -Wl,-z,defs   -Wl,-init,__uClibc_init  -Wl,-soname=libc.so.0
> > -nostdlib -o lib/libuClibc-0.9.34-git.so  -Wl,--whole-archive libc/libc_so.a
> > -Wl,--no-whole-archive ./lib/interp.os ./lib/ld-uClibc.so.0
> > ./lib/uclibc_nonshared.a
> > /opt/users/ig/code/buildroot-git/output/host/usr/lib/gcc/arm-unknown-linux-uclibcgnueabi/4.7.0/libgcc.a 
> > libc/libc_so.a(lockf.os): In function `__GI_lockf':
> > /opt/users/ig/code/buildroot-git/output/toolchain/uClibc/libc/misc/file/lockf.c:73:
> > undefined reference to `_Unwind_Resume'
> > libc/libc_so.a(lockf.os):(.ARM.extab+0x0): undefined reference to
> > `__gcc_personality_v0'
> > collect2: error: ld returned 1 exit status
> 
> This GCC bug was fixed already.
> See http://gcc.gnu.org/PR51117

Sorry, I think the mentioned GCC bug is unrelated.

/opt/users/ig/code/buildroot-git/output/toolchain/uClibc/libc/misc/file/lockf.c:73: undefined reference to `_Unwind_Resume'

When compiling buildroot 2013.11 with uclibc's DODEBUG and buildroot's BR2_PREFER_STATIC_LIB I get the same error. Without this DODEBUG uclibc-option it works fine. No matter if I use gcc 4.7.3 or 4.8.2.

But I found a fix from January 2013 that you committed for this problem in uclibc. It is about a missing dependency to libgcc_eh. When I apply this patch then I can compile without this linker error even when using DODEBUG.

Sadly this fix is not yet available in the current uclibc release (0.9.33.2).

commit: http://git.uclibc.org/uClibc/commit/?id=8d31a6e50db423b89082b64a3250eec1b94a7456
branch: http://git.uclibc.org/uClibc/commit/?id=refs/heads/master

with -O0 we (e.g. lockf) might end up with references to
_Unwind_Resume, so pull in gcc_eh in this case..

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop at gmail.com>
---
 Rules.mak              |    4 ++++
 libc/misc/file/lockf.c |    5 +----
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/Rules.mak b/Rules.mak
index 8943fbf..9d621b5 100644
--- a/Rules.mak
+++ b/Rules.mak
@@ -804,6 +804,10 @@ ASFLAGS = $(ASFLAG_--noexecstack)
 
 LIBGCC_CFLAGS ?= $(CFLAGS) $(CPU_CFLAGS-y)
 $(eval $(call cache-output-var,LIBGCC,$(CC) $(LIBGCC_CFLAGS) -print-libgcc-file-name))
+$(eval $(call cache-output-var,LIBGCC_EH,$(CC) $(LIBGCC_CFLAGS) -print-file-name=libgcc_eh.a))
+# with -O0 we (e.g. lockf) might end up with references to
+# _Unwind_Resume, so pull in gcc_eh in this case..
+LIBGCC += $(if $(DODEBUG),$(LIBGCC_EH))
 LIBGCC_DIR:=$(dir $(LIBGCC))
 
 # moved from libpthread/linuxthreads
diff --git a/libc/misc/file/lockf.c b/libc/misc/file/lockf.c
index 4e398cd..56b3aac 100644
--- a/libc/misc/file/lockf.c
+++ b/libc/misc/file/lockf.c
@@ -16,15 +16,12 @@
    see <http://www.gnu.org/licenses/>.  */
 
 #include <features.h>
-
 #include <sys/types.h>
-#include <unistd.h>
 #include <fcntl.h>
+#include <unistd.h>
 #include <errno.h>
 #include <string.h>
 
-
-
 /* lockf is a simplified interface to fcntl's locking facilities.  */
 
 int lockf (int fd, int cmd, off_t len)

I've just stumbled across the same bug, thought it took several days to narrow it down and eventually find this bug report.

The symptoms are practically identical:
- cross-compiling for ARM target
- executable is linked with -lpthread (even when it doesn't use threads)
- throw() occurs in a subroutine, not in the try/catch block.
- the subroutine allocates some local object too (likely avoids inlining)
- compile with -O1 or higher, which enables -fomit-frame-pointer.
- uClibc-0.9.33.2, NPTL

Differences:
- I can trigger the SIGABRT in a single compilation unit.
- The catch block can match the thrown exception, or it can be "..." (both fail)
- I'm targeting cortex A9 rather than A8.
- I've used buildroot 2013.08 and also 2014.08, both failed.
- External toolchains from Codesourcery do not have this problem.

Here's my test program. It crashes with SIGABRT if the above conditions are met. If compiled with -O0 or -fno-omit-frame-pointer then it runs fine and prints "CATCH" as expected.

/*
 * arm-linux-gcc -O1 -Wall -o cpptest cpptest.cpp -lpthread
 */
#include <iostream>
#include <string>
#include <sstream>
#include <stdexcept>

void subroutine(void) throw(std::out_of_range)
{
        std::ostringstream strStream;
        throw std::out_of_range("foobar");
}

int main()
{
        try
        {
                subroutine();
        }
        catch (...)  // catch (std::out_of_range) also fails
        {
                std::cerr << "CATCH" << std::endl;
        }
        return 0;
}


Please let me know if I can provide any more debug info.

I'm also testing the patch from comment 9, however so far it does not seem to fix the issue for me.

Minor typo:

> /*
>  * arm-linux-gcc -O1 -Wall -o cpptest cpptest.cpp -lpthread
>  */

should of course be arm-linux-g++ not gcc

I also decided to try today's uClibc snapshot, which should include the patch, but after a full rebuild, the SIGABRT behaviour persists.