[uml-devel] driver crash under UML

[David F. <df...@ma...>]

I updated the cvs sources for UML yesterday, but today it gives me,
cvs [status aborted]: recv() from server cvs.user-mode-linux.sourceforge.net: EOF

This is with 2.4.6 official kernel with the UML cvs files.  I was
wanting to debug a driver I'm working on, but it crashes before it is
barely up.  I started looking at UML with 2.4.5 and it did the same.
I included the source code for the minimal module to get it to crash.

On a real 2.4.5 linux kernel it succeeds
about to run init_waitqueue_head
about to run wake_up_interruptible
success now unloading

On UML 2.4.6
usermode:/mnt/tick/home/dfries/helper_apps/apps/kernel_modules/wait_module#
insmod wake_up.o
about to run init_waitqueue_head
about to run wake_up_interruptible
then it panics

If I put a break on __wake_up in the debugger and run I see this,

(gdb) bt 
#0  __wake_up (q=0x1017c4e0, mode=1, nr=1) at sched.c:749
#1  0x1000a1e8 in printk (
    fmt=0x518001e0 "about to run wake_up_interruptible\n") at printk.c:311
#2  0x51800092 in ?? ()
#3  0x100d3563 in execute_syscall (regs={regs = {134587808, 134722848, 
        134723556, 134605864, 1367343104, 3212831420, 4294967258, 43, 43, 0, 
        0, 128, 134546852, 35, 642, 3212831396, 43}}) at syscall_kern.c:332
#4  0x100d3690 in syscall_handler (unused=0x0) at syscall_user.c:80
(gdb) c
Continuing.

Breakpoint 4, __wake_up (q=0x518001e0, mode=134722932, nr=1348779776)
    at sched.c:749
749     {
(gdb) bt
#0  __wake_up (q=0x518001e0, mode=134722932, nr=1348779776) at sched.c:749
#1  0x518000a6 in ?? ()
#2  0x100d3563 in execute_syscall (regs={regs = {134587808, 134722848, 
        134723556, 134605864, 1367343104, 3212831420, 4294967258, 43, 43, 0, 
        0, 128, 134546852, 35, 642, 3212831396, 43}}) at syscall_kern.c:332
#3  0x100d3690 in syscall_handler (unused=0x0) at syscall_user.c:80

It looks like the mode and nr values are screwed up for the 2nd case,
but looking at the pre-processor output shows the code as being,
int init_module(void)
{
        printk("about to run init_waitqueue_head\n");
        init_waitqueue_head(&wait_list);
        printk("about to run wake_up_interruptible\n");
        __wake_up(( &wait_list ),1 , 1) ;
        printk("success now unloading\n");
        return -1;
}

could gdb be conflused?


-- 
		+---------------------------------+
		|      David Fries                |
		|      df...@ma...        |
		+---------------------------------+