Re: 2.6.26-rc5-mm1: uml link error

[Miklos Szeredi]

> From: Peter Oberparleiter <peter.oberparleiter@xxxxxxxxxx>
> 
> Fix for linker error on UML:
> 
> /usr/lib64/gcc/x86_64-suse-linux/4.2.1/../../../../x86_64-suse-linux/bin/ld:arch/um/kernel/vmlinux.lds:267: syntax error
> 
> The error is triggered by the use of SORT(CONSTRUCTORS) in the UML
> linker script which conflicts with the kernel-call-constructors patch.
> Here is what the ld info page says about sorting constructors:
> 
>      If you are using the GNU C++ support for initialization priority,
>      which provides some control over the order in which global
>      constructors are run, you must sort the constructors at link time
>      to ensure that they are executed in the correct order.
> 
> As there's no C++ code inside the kernel it should be safe to remove
> the SORT construct.

Hmm, uml still doesn't boot with this patch, it dies while calling the
constructors.  So maybe that SORT contruct is still needed?

Miklos



mszeredi@tucsk:/store/uml> /store/quilt/linux/linux umid=uml
Locating the bottom of the address space ... 0x0
Locating the top of the address space ... 0xffffd000
Core dump limits :
        soft - NONE
        hard - NONE
Checking that ptrace can change system call numbers...OK
Checking syscall emulation patch for ptrace...missing
Checking for tmpfs mount on /dev/shm...nothing mounted on /dev/shm
Checking PROT_EXEC mmap in /tmp/...OK
Checking for the skas3 patch in the host:
  - /proc/mm...not found: No such file or directory
  - PTRACE_FAULTINFO...not found
  - PTRACE_LDT...not found
UML running in SKAS0 mode
Adding 15208448 bytes to physical memory to account for exec-shield gap
Aborted (core dumped)
mszeredi@tucsk:/store/uml> gdb /store/quilt/linux/linux core
GNU gdb 6.6.50.20070726-cvs
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GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
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This GDB was configured as "x86_64-suse-linux"...
Using host libthread_db library "/lib64/libthread_db.so.1".

warning: Can't read pathname for load map: Input/output error.
Reading symbols from /lib/libutil.so.1...done.
Loaded symbols for /lib/libutil.so.1
Reading symbols from /lib/libc.so.6...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
Core was generated by `/store/quilt/linux/linux umid=uml'.
Program terminated with signal 6, Aborted.
#0  0xffffe430 in __kernel_vsyscall ()
(gdb) bt
#0  0xffffe430 in __kernel_vsyscall ()
#1  0xf7e598f5 in raise () from /lib/libc.so.6
#2  0xf7e5b1e1 in abort () from /lib/libc.so.6
#3  0x0807173d in os_dump_core () at arch/um/os-Linux/util.c:119
#4  0x08061d07 in panic_exit (self=0x8451594, unused1=0, unused2=0x8471f20) at arch/um/kernel/um_arch.c:233
#5  0x0809a2ea in notifier_call_chain (nl=0x84594ec, val=0, v=0x8471f20, nr_to_call=-1, nr_calls=0x0)
    at kernel/notifier.c:85
#6  0x0809a3e0 in __atomic_notifier_call_chain (nh=0x84594dc, val=0, v=0x8471f20, nr_to_call=-1, nr_calls=0x0)
    at kernel/notifier.c:174
#7  0x0809a41f in atomic_notifier_call_chain (nh=0x84594dc, val=0, v=0x8471f20) at kernel/notifier.c:183
#8  0x0807e88a in panic (fmt=0x83dd7be "Segfault with no mm") at kernel/panic.c:104
#9  0x08061922 in segv (fi={error_code = 21, cr2 = 4294967295, trap_no = 14}, ip=4294967295, is_user=0,
    regs=0x844fc70) at arch/um/kernel/trap.c:176
#10 0x080616c7 in segv_handler (sig=11, regs=0x6) at arch/um/kernel/trap.c:152
#11 0x0806ff00 in sig_handler_common (sig=11, sc=0x844fd24) at arch/um/os-Linux/signal.c:49
#12 0x0806ff87 in sig_handler (sig=11, sc=0x844fd24) at arch/um/os-Linux/signal.c:81
#13 0x0807011d in handle_signal (sig=2894, sc=0x844fd24) at arch/um/os-Linux/signal.c:158
#14 0x08071fb8 in hard_handler (sig=11) at arch/um/os-Linux/sys-i386/signal.c:12
#15 <signal handler called>
#16 0xffffffff in ?? ()
#17 0x08049793 in do_ctors () at init/main.c:706
#18 0x080499cc in do_basic_setup () at init/main.c:789
#19 0x08049a43 in kernel_init (unused=0x0) at init/main.c:897
#20 0x0806f241 in run_kernel_thread (fn=0x8049a10 <kernel_init>, arg=0x0, jmp_ptr=0xa860b50)
    at arch/um/os-Linux/process.c:267
#21 0x0805ed02 in new_thread_handler () at arch/um/kernel/process.c:151
#22 0x00000000 in ?? ()
(gdb) 


Miklos
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