SIGILL on gdbserver/ARM/uclibc

SIGILL on gdbserver/ARM/uclibc

[Harald Schiöberg]

I know that this issue is on the list every other year, but I found no
working solution for my problem.

I'm currently trying to run gdb/gdbserver on OpenWRT/ARM
(uclibc-0.9.29/gcc-4.1.2, tried gdb 6.3 and 6.7.1,
target is xscale (armv5te), host is ubuntu x86_64,
OpenWRT builds gdb with
                gdb_cv_func_sigsetjmp=yes \
                $(PKG_BUILD_DIR)/configure \
                --prefix=$(TOOLCHAIN_DIR) \
                --build=$(GNU_HOST_NAME) \
                --host=$(GNU_HOST_NAME) \
                --target=$(REAL_GNU_TARGET_NAME) \
                $(DISABLE_NLS) \
                --without-uiout \
                --disable-tui --disable-gdbtk --without-x \
                --without-included-gettext \
                --enable-threads \
#	 --disable-gdbmi ## this was commented out for 6.7.1 to compile


I'm getting SIGILL after a breakpoint on the target.

some session-log from 6.7.1:

(gdb)  target remote 172.17.2.190:4000
Remote debugging using 172.17.2.190:4000
warning: Unable to find dynamic linker breakpoint function.
GDB will be unable to debug shared library initializers
and track explicitly loaded dynamic code.
0x400009d0 in ?? ()
(gdb)  b main
Note: breakpoint 1 also set at pc 0x8570.
Breakpoint 2 at 0x8570: file hello.c, line 6.
(gdb) c
Continuing.

Program received signal SIGILL, Illegal instruction.
0x00008574 in main () at hello.c:6
6               for (i=0; i< 10; i++)
(gdb) s

Program terminated with signal SIGILL, Illegal instruction.
The program no longer exists.
(gdb) show osabi
The current OS ABI is "auto" (currently "GNU/Linux").
The default OS ABI is "GNU/Linux".
(gdb) set osabi GNU/Linux
(gdb) show osabi
The current OS ABI is "GNU/Linux".
The default OS ABI is "GNU/Linux".
(gdb) target remote 172.17.2.190:4000
Remote debugging using 172.17.2.190:4000
warning: Unable to find dynamic linker breakpoint function.
GDB will be unable to debug shared library initializers
and track explicitly loaded dynamic code.
0x400009d0 in ?? ()
(gdb)  b main
Note: breakpoints 1 and 2 also set at pc 0x8570.
Breakpoint 3 at 0x8570: file hello.c, line 6.
(gdb)  c
Continuing.

Program received signal SIGILL, Illegal instruction.
0x00008574 in main () at hello.c:6
6               for (i=0; i< 10; i++)
(gdb) s
breakpoint.c:7845: internal-error: insert_single_step_breakpoint:
Assertion `single_step
_breakpoints[1] == NULL' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) y


-- 
Harald Schiöberg
Technische Universität Berlin | T-Laboratories | FG INET
www: http://www.net.t-labs.tu-berlin.de
Phone: +49-(0)30-8353-58476 | Fax: +49-(0)391 534 783 47

Re: SIGILL on gdbserver/ARM/uclibc

[Daniel Jacobowitz]

On Mon, Jan 07, 2008 at 11:30:42AM +0100, Harald Schiöberg wrote:
> I'm getting SIGILL after a breakpoint on the target.

Figure out what instruction GDB is inserting, by using "set debug
remote 1" and watching the memory writes.  Try running that
instruction using asm("") on your target.  If it doesn't generate a
SIGTRAP, then either GDB is confused and using the wrong instruction,
or your kernel is confused and generating the wrong signal.

> (gdb)  target remote 172.17.2.190:4000
> Remote debugging using 172.17.2.190:4000
> warning: Unable to find dynamic linker breakpoint function.
> GDB will be unable to debug shared library initializers
> and track explicitly loaded dynamic code.

See "set sysroot".


-- 
Daniel Jacobowitz
CodeSourcery

Re: SIGILL on gdbserver/ARM/uclibc

[Harald Schiöberg]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Daniel Jacobowitz wrote:
> On Mon, Jan 07, 2008 at 11:30:42AM +0100, Harald Schiöberg wrote:
>> I'm getting SIGILL after a breakpoint on the target.
> 
> Figure out what instruction GDB is inserting, by using "set debug
> remote 1" and watching the memory writes.  Try running that
> instruction using asm("") on your target.  If it doesn't generate a
> SIGTRAP, then either GDB is confused and using the wrong instruction,
> or your kernel is confused and generating the wrong signal.

uhm, where do I find some info about reading the debug output.


(gdb) set debug remote 1
(gdb) set sysroot /data/harald/root/
(gdb) target remote 172.17.2.190:4000
Remote debugging using 172.17.2.190:4000
Sending packet: $qSupported#37...Ack
Packet received:
PacketSize=7cf;QPassSignals+;qXfer:libraries:read+;qXfer:auxv:read+
Packet qSupported (supported-packets) is supported
Sending packet: $Hc-1#09...Ack
Packet received: E01
Sending packet: $qC#b4...Ack
Packet received: QC902
Sending packet: $qOffsets#4b...Ack
Packet received:
Sending packet: $?#3f...Ack
Packet received: T050b:00000000;0d:be968e10;0f:400009d0;
Sending packet: $m10668,4#d2...Ack
Packet received: 00000000
Sending packet: $m10668,4#d2...Ack
Packet received: 00000000
Sending packet: $m10668,4#d2...Ack
Packet received: 00000000
warning: no loadable sections found in added symbol-file
/data/harald/root/lib/ld-uClibc
.so.0
Sending packet: $qSymbol::#5b...Ack
Packet received: OK
Packet qSymbol (symbol-lookup) is supported
warning: Unable to find dynamic linker breakpoint function.
GDB will be unable to debug shared library initializers
and track explicitly loaded dynamic code.
Sending packet: $qXfer:auxv:read::0,7ca#a5...Ack
Packet received:
l\000\000\000\020\000\000\000\223\000\000\000\006\000\000\020\000\000\0
00\000\021\000\000\000d\000\000\000\003\000\000\2004\000\000\000\004\000\000\000
\000\00
0\000\005\000\000\000\006\000\000\000\a@\000\000\000\000\000\000\b\000\000\000\000\000\0
00\000\t\000\000\204L\000\000\000\013\000\000\000\000\000\000\000\f\000\000\000\000\000\
000\000\r\000\000\000\000\000\000\000\016\000\000\000\000\000\000\000\027\000\000\000\00
0\000\000\000\017�\226\216�000\000\000\000\000\000\000\000
Sending packet: $m400009d0,4#8e...Ack
Packet received: e1a0000d
Sending packet: $m400009cc,4#c0...Ack
Packet received: 00000000
Sending packet: $m400009d0,4#8e...Ack
Packet received: e1a0000d
Sending packet: $m400009cc,4#c0...Ack
Packet received: 00000000
Sending packet: $m400009d0,4#8e...Ack
Packet received: e1a0000d
Sending packet: $m400009d0,4#8e...Ack
Packet received: e1a0000d
Sending packet: $m400009d0,4#8e...Ack
Packet received: e1a0000d
0x400009d0 in ?? ()
Sending packet: $qSymbol::#5b...Ack
Packet received: OK
(gdb) b main
Breakpoint 1 at 0x8570: file hello.c, line 6.
(gdb) c
Continuing.
Sending packet: $Z0,844c,4#19...Ack
Packet received:
Packet Z0 (software-breakpoint) is NOT supported
Sending packet: $m844c,4#d0...Ack
Packet received: e3a0b000
Sending packet: $X844c,0:#f1...Ack
Packet received: OK
binary downloading suppported by target
Sending packet: $X844c,4:�237\000\001#84...Ack
Packet received: OK
Sending packet: $m8570,4#a1...Ack
Packet received: e3a03000
Sending packet: $X8570,4:�237\000\001#55...Ack
Packet received: OK
Sending packet: $QPassSignals:e;10;14;17;1a;1b;1c;21;24;25;4c;#8f...Ack
Packet received: OK
Sending packet: $vCont?#49...Ack
Packet received: vCont;c;C;s;S
Packet vCont (verbose-resume) is supported
Sending packet: $vCont;c#a8...Ack
Packet received: T040b:be968d8c;0d:be968d7c;0f:00008574;

Program received signal SIGILL, Illegal instruction.
Sending packet: $X844c,4:ã °\000#28...Ack
Packet received: OK
Sending packet: $X8570,4:�\000#79...Ack
Packet received: OK
Sending packet: $m8574,4#a5...Ack
Packet received: e50b3010
Sending packet: $m8570,4#a1...Ack
Packet received: e3a03000
Sending packet: $m8574,4#a5...Ack
Packet received: e50b3010
Sending packet: $m8570,4#a1...Ack
Packet received: e3a03000
Sending packet: $m8574,4#a5...Ack
Packet received: e50b3010
Sending packet: $m8574,4#a5...Ack
Packet received: e50b3010
Sending packet: $m8574,4#a5...Ack
Packet received: e50b3010
0x00008574 in main () at hello.c:6
6               for (i=0; i< 10; i++)



> 
>> (gdb)  target remote 172.17.2.190:4000
>> Remote debugging using 172.17.2.190:4000
>> warning: Unable to find dynamic linker breakpoint function.
>> GDB will be unable to debug shared library initializers
>> and track explicitly loaded dynamic code.
> 
> See "set sysroot".




	

- --
Harald Schiöberg
Technische Universität Berlin | T-Laboratories | FG INET
www: http://www.net.t-labs.tu-berlin.de
Phone: +49-(0)30-8353-58476 | Fax: +49-(0)391 534 783 47
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Re: SIGILL on gdbserver/ARM/uclibc

[Daniel Jacobowitz]

On Mon, Jan 07, 2008 at 02:49:21PM +0100, Harald Schiöberg wrote:
> uhm, where do I find some info about reading the debug output.

In the manual.  But I can pick out the instruction for you, here...

> Sending packet: $X844c,4:�237\000\001#84...Ack

Of course your mailer seems to have garbled that a little so I can't
tell exactly what character it was.  But it's something 0237 000 001.
That's arm_linux_arm_be_breakpoint.  If you're using
arm-linux-gnueabi, it's wrong; if you're using old-ABI it should be
correct.

> warning: no loadable sections found in added symbol-file
> /data/harald/root/lib/ld-uClibc
> .so.0

Is that really the right file?  It looks corrupt.

-- 
Daniel Jacobowitz
CodeSourcery

Re: SIGILL on gdbserver/ARM/uclibc

[Harald Schiöberg]

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Hash: SHA1

Daniel Jacobowitz wrote:
> On Mon, Jan 07, 2008 at 02:49:21PM +0100, Harald Schiöberg wrote:
>> uhm, where do I find some info about reading the debug output.
> 
> In the manual.  But I can pick out the instruction for you, here...
> 
>> Sending packet: $X844c,4:�237\000\001#84...Ack
> 
> Of course your mailer seems to have garbled that a little so I can't
> tell exactly what character it was.  But it's something 0237 000 001.
> That's arm_linux_arm_be_breakpoint.  If you're using
> arm-linux-gnueabi, it's wrong; if you're using old-ABI it should be
> correct.
> 

thank you, for everyone searching the archive:
	"set arm abi AAPCS" (instead of default APCS)
fixed it.


>> warning: no loadable sections found in added symbol-file
>> /data/harald/root/lib/ld-uClibc
>> .so.0
> 
> Is that really the right file?  It looks corrupt.

not yet sure what it is, but:
root@OpenWrt:/nfs/tmp# ldd ./hello
        libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x4000e000)
        libc.so.0 => /lib/libc.so.0 (0x40020000)
        libc.so.0 => /lib/libc.so.0 (0x40083000)
        ld-uClibc.so.0 => /lib/ld-uClibc.so.0 (0x40000000)

he furthermore now claims:
warning: no loadable sections found in added symbol-file
/data/harald/root/lib/libgcc_s.so.1
warning: no loadable sections found in added symbol-file
/data/harald/root/lib/libc.so.0

I have to dig a little bit deeper, most likely OpenWRT is guilty here,
unless gdb does something really weird.

Thanks a lot
	Harald


- --
Harald Schiöberg
Technische Universität Berlin | T-Laboratories | FG INET
www: http://www.net.t-labs.tu-berlin.de
Phone: +49-(0)30-8353-58476 | Fax: +49-(0)391 534 783 47
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