[uml-devel] problems with UML, issues with includes

[uml-devel] problems with UML, issues with includes

[Chris Friesen]

I'm having issues with UML.

I've got a rootfs that used to work with an older UML.  With 2.4.24, I 
try and boot with the following arguments:

./linux-2.4.24  mem=256M con0=fd:0,fd:1 con=pts ubd0=test,rootfs debug 
msp_view=build_neptune_2.0_int11

The msp_view thing causes additional mounts to be created at init time. 
  However, I get a bunch of errors in my console window when I try to 
log in:

ed Hat Linux release 8.0 (Psyche)
Plankton/CELP 2.5.0 - Kernel 2.4.24-1um on an i686

(none) login: Registering fd 47 twice
Irqs : 3, 3
Ids : 0xa022c3f8, 0xa022c3f8
Registering fd 47 twice
Irqs : 3, 3
Ids : 0xa022c3f8, 0xa022c3f8



If I then keep going, I end up with a whole bunch of lines like:

Failed to forward -1359446016 to pid 16452, err = 9


As part of my efforts to try and debug this, I wanted to dump out the 
names of the processes that were calling os_set_owner().  Accordingly in 
  um/os/file.c I included <linux/sched.c> and wrote some code with 
appropriate locking around the tasklist_lock so that I could match the 
pid against the process name.

When I compiled, it grabbed the sched.h from /usr/include rather than 
from the kernel build, and everything blew up.

So I guess I'm asking for help on two fronts.  1) How do I fix the build 
process to pick up the kernel includes (and why doesn't it do that by 
default?).  2) Any ideas why I'm getting the descriptor thing?

Thanks,

Chris

-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com




-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML, issues with includes

[Jeff Dike]

cfriesen@nortelnetworks.com said:
> 1) How do I fix the build  process to pick up the kernel includes (and
> why doesn't it do that by  default?).  

You don't.  The host's libc headers and the UML pool's kernel headers are
fundamentally incompatible.  You can't mix them, as you're trying to do
by including sched.h into a userspace file.

> 2) Any ideas why I'm getting
> the descriptor thing?

No, but get a stack trace or two from that printk, and that should help figure
it out.

				Jeff



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML, issues with includes

[Chris Friesen]

Jeff Dike wrote:
> cfriesen@nortelnetworks.com said:
> 
>>1) How do I fix the build  process to pick up the kernel includes (and
>>why doesn't it do that by  default?).  
>>
> 
> You don't.  The host's libc headers and the UML pool's kernel headers are
> fundamentally incompatible.  You can't mix them, as you're trying to do
> by including sched.h into a userspace file.

Maybe I'm just confused about how the various things get compiled.  In a 
normal kernel build, including <linux/sched.h> gets you the kernel 
headers, not the libc headers. I had assumed that I would be able to get 
at the UML kernel's sched.h from within the arch/um code.  Is this a 
false assumption?  Or am I just doing it wrong?


>>2) Any ideas why I'm getting
>>the descriptor thing?
>>
> 
> No, but get a stack trace or two from that printk, and that should help figure
> it out.

Here's a backtrace from just where the code would print the registering 
twice message.  Am I right in assuming that since we're hitting this it 
seems to indicate some messed-up reference counting somewhere?


#0  activate_fd (irq=3, fd=47, type=1, dev_id=0xa02309f8) at irq_user.c:157
#1  0xa00cf9bd in um_request_irq (irq=3, fd=47, type=1,
     handler=0xa010e230 <line_write_interrupt>, irqflags=872415232,
     devname=0xa01e7e85 "console-write", dev_id=0xa02309f8) at irq.c:430
#2  0xa010e326 in line_setup_irq (fd=47, input=1, output=1, data=0xa02309f8)
     at line.c:211
#3  0xa010d0b9 in enable_chan (chans=0xa0230a00, data=0xa02309f8)
     at chan_kern.c:164
#4  0xa010e458 in line_open (lines=0xa02309a0, tty=0xaf1f7000, 
opts=0xa0230920)
     at line.c:258
#5  0xa010cb99 in open_console (tty=0xaf1f7000) at stdio_console.c:135
#6  0xa00e391f in tty_open (inode=0xafc13c00, filp=0xafe7ef20) at 
tty_io.c:1433
#7  0xa0084d94 in devfs_open (inode=0xafc13c00, file=0xafe7ef20) at 
base.c:2799
#8  0xa0035e18 in dentry_open (dentry=0xafcd15a0, mnt=0xa032f320, flags=2)
     at open.c:698
#9  0xa0035d0b in filp_open (filename=0xaff49000 "/dev/ttys/1", flags=2,
     mode=0) at open.c:656
#10 0xa003607a in sys_open (filename=0x9ffffd20 "/dev/ttys/1", flags=2, 
mode=0)
     at open.c:798
#11 0xa00d97ec in execute_syscall_tt (r=0xaefd8274) at syscall_kern.c:120
#12 0xa00d98a9 in syscall_handler_tt (sig=12, regs=0xaefd8274)
     at syscall_user.c:37
#13 0xa00da9bb in sig_handler_common_tt (sig=12, sc_ptr=0xaefdbd28)
---Type <return> to continue, or q <return> to quit---
     at trap_user.c:37
#14 0xa00d70dd in sig_handler (sig=12, sc=
       {gs = 0, __gsh = 0, fs = 0, __fsh = 0, es = 43, __esh = 0, ds = 
43, __dsh = 0, edi = 2684353860, esi = 2684353824, ebp = 2684354024, esp 
= 2684353800, ebx = 2684353824, edx = 0, ecx = 2, eax = 4294967258, 
trapno = 14, err = 4, eip = 1074733544, cs = 35, __csh = 0, eflags = 
582, esp_at_signal = 2684353800, ss = 43, __ssh = 0, fpstate = 
0xaefdbd80, oldmask = 134283264, cr2 = 1074737568})
     at trap_user.c:101
#15 <signal handler called>
#16 0x400f21e8 in ?? ()
#17 0x08049799 in ?? ()
#18 0x4002f9a7 in ?? ()


-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

Re: [uml-devel] Re: problems with UML, issues with includes

[BlaisorBlade]

Alle 16:08, martedì 2 marzo 2004, Chris Friesen ha scritto:
> Jeff Dike wrote:
>
> Maybe I'm just confused about how the various things get compiled.  In a
> normal kernel build, including <linux/sched.h> gets you the kernel
> headers, not the libc headers.

> I had assumed that I would be able to get
> at the UML kernel's sched.h from within the arch/um code.  Is this a
> false assumption?  Or am I just doing it wrong?

Inside arch/um, there are some files which can include *only* the kernel 
includes, and some files which can include *only* the libc includes; 
os/file.c is of the second type. In the directory Makefile, the files listed 
in USER_OBJS are of the second type:

USER_OBJS := $(foreach file,file.o process.o tty.o,$(obj)/$(file))
i.e. file.o is listed. Note this idiom:

 USER_OBJS := $(filter %_user.o,$(obj-y) $(obj-m)) fd.o ...

the $(filter ) part means a "grep" for *_user.o: i.e. every file ending in 
_user.c is compiled against libc headers.

-- 
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id\x1356&alloc_id438&opÌk
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML, issues with includes

[Jeff Dike]

cfriesen@nortelnetworks.com said:
> Am I right in assuming that since we're hitting this it  seems to
> indicate some messed-up reference counting somewhere? 

It would appear so.

This is inside an if line->count == 0

> #4  0xa010e458 in line_open (lines=0xa02309a0, tty=0xaf1f7000, 
> opts=0xa0230920) at line.c:258

and the place that decrements line->count does this:

	if(line->count == 0)
		line_disable(line, -1);

which should ensure that the interrupt is disabled.

Could you get stack traces from activate_fd and deactivate_fd for this irq?
We need to see how the count is becoming 0 without the interrupt being turned
off.

				Jeff



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML, issues with includes

[Chris Friesen]

I've found something interesting.

I'm hitting a code path in activate_fd(), where the call to um_kmalloc() 
returns a chunk of memory that is still pointed to in the active_fds 
linked list!

Hence, it updates the fd and type to the ones passed in, then scans the 
list and of course it finds a conflict and starts complaining about 
duplicate activations.

Somehow memory is being freed without it being removed from the 
active_fds list.

I put a check in kfree() to scan the arg against the active_fds list. 
Here's the backtrace of the first call that tried to free up memory 
still on the active_fds list.


#0  kfree (objp=0xa032c820) at slab.c:1622
#1  0xa00d03d6 in activate_fd (irq=3, fd=47, type=1, dev_id=0xa02309f8)
     at irq_user.c:230
#2  0xa00cf9ed in um_request_irq (irq=3, fd=47, type=1,
     handler=0xa010e340 <line_write_interrupt>, irqflags=872415232,
     devname=0xa01e7fa5 "console-write", dev_id=0xa02309f8) at irq.c:430
#3  0xa010e436 in line_setup_irq (fd=47, input=1, output=1, data=0xa02309f8)
     at line.c:211
#4  0xa010d1c9 in enable_chan (chans=0xa0230a00, data=0xa02309f8)
     at chan_kern.c:164
#5  0xa010e568 in line_open (lines=0xa02309a0, tty=0xaf0ec000, 
opts=0xa0230920)
     at line.c:258
#6  0xa010cca9 in open_console (tty=0xaf0ec000) at stdio_console.c:135
#7  0xa00e3a2f in tty_open (inode=0xafc27c00, filp=0xaf2d9a60) at 
tty_io.c:1433
#8  0xa0084dc4 in devfs_open (inode=0xafc27c00, file=0xaf2d9a60) at 
base.c:2799
#9  0xa0035e48 in dentry_open (dentry=0xafc5d5a0, mnt=0xa032f320, flags=2)
     at open.c:698
#10 0xa0035d3b in filp_open (filename=0xaff49000 "/dev/ttys/1", flags=2,
     mode=0) at open.c:656
#11 0xa00360aa in sys_open (filename=0x9ffffd20 "/dev/ttys/1", flags=2, 
mode=0)
     at open.c:798
#12 0xa00d98fc in execute_syscall_tt (r=0xaefd8274) at syscall_kern.c:120
#13 0xa00d99b9 in syscall_handler_tt (sig=12, regs=0xaefd8274)
---Type <return> to continue, or q <return> to quit---
     at syscall_user.c:37
#14 0xa00daacb in sig_handler_common_tt (sig=12, sc_ptr=0xaefdbd28)
     at trap_user.c:37
#15 0xa00d71ed in sig_handler (sig=12, sc=
       {gs = 0, __gsh = 0, fs = 0, __fsh = 0, es = 43, __esh = 0, ds = 
43, __dsh = 0, edi = 2684353860, esi = 2684353824
, ebp = 2684354024, esp = 2684353800, ebx = 2684353824, edx = 0, ecx = 
2, eax = 4294967258, trapno = 14, err = 4, eip =
  1074733544, cs = 35, __csh = 0, eflags = 582, esp_at_signal = 
2684353800, ss = 43, __ssh = 0, fpstate = 0xaefdbd80, ol
dmask = 134283264, cr2 = 1074737568})
     at trap_user.c:101
#16 <signal handler called>
#17 0x400f21e8 in ?? ()
#18 0x08049799 in ?? ()
#19 0x4002f9a7 in ?? ()




Chris



-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML, issues with includes

[Jeff Dike]

cfriesen@nortelnetworks.com said:
> #1  0xa00d03d6 in activate_fd (irq=3, fd=47, type=1,
> dev_id=0xa02309f8) at irq_user.c:230 

Why don't your line numbers match mine?  The kfree you seem to be talking
about is this:

   211   out_unlock:
   212          irq_unlock(flags);
   213          kfree(new_fd);
   214   out:

And I totally don't see a problem there.  new_fd isn't on any lists when it's
freed there.

				Jeff



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML, issues with includes

[Chris Friesen]

Jeff Dike wrote:
> cfriesen@nortelnetworks.com said:
> 
>>#1  0xa00d03d6 in activate_fd (irq=3, fd=47, type=1,
>>dev_id=0xa02309f8) at irq_user.c:230 
>>
> 
> Why don't your line numbers match mine?  

I've added debug statements.

The kfree you seem to be talking
> about is this:

> 
>    211   out_unlock:
>    212          irq_unlock(flags);
>    213          kfree(new_fd);
>    214   out:
> 
> And I totally don't see a problem there.  new_fd isn't on any lists when it's
> freed there.

As mentioned in my other message, I'm seeing um_kmalloc() return a 
new_fd address that is *already* on the active_fds list.  Hence it ends 
up looking like a dupe, hence we end up calling kfree() on an address 
that is still on the active_fds list.

I made the following changes within activate_fd() to try and see what's 
going on.  If I set a breakpoint at the "redo=1" line and then step 
through the code, I end up in a continuous loop getting the same value 
for the return code of um_kmalloc().  There's something fishy going on 
here....

get_mem:
	new_fd = um_kmalloc(sizeof(*new_fd));	
	err = -ENOMEM;
	if(new_fd == NULL)
		goto out;
	
	redo = 0;
	flags = irq_lock();
	for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
		
		if (irq_fd == new_fd) {
			redo = 1;
		}
	}
	irq_unlock(flags);
	
	if (redo)
		goto get_mem;


Chris


-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML -- new data with memory debugging on

[Chris Friesen]

I turned on memory debugging, and got the following.  Line 1439 in 
slab.c is

/* Either write before start, or a double free. */

Here's the backtrace:

Breakpoint 1, panic (fmt=0xa01e2d8a "kernel BUG at %s:%d!\n") at panic.c:60
60              bust_spinlocks(1);
(gdb) bt
#0  panic (fmt=0xa01e2d8a "kernel BUG at %s:%d!\n") at panic.c:60
#1  0xa002dc8a in kfree (objp=0xa032c89c) at slab.c:1439
#2  0xa0103ac8 in hostfs_read_super (sb=0xaf332400, data=0xaf036000, 
silent=0)
     at hostfs_kern.c:932
#3  0xa003cae9 in get_sb_nodev (fs_type=0xa022d62c, flags=0,
     dev_name=0xaf037000 "none", data=0xaf036000) at super.c:756
#4  0xa003cc82 in do_kern_mount (fstype=0xaf0d8000 "hostfs", flags=0,
     name=0xaf037000 "none", data=0xaf036000) at super.c:808
#5  0xa004fd62 in do_add_mount (nd=0xaefcbb94, type=0xaf0d8000 "hostfs",
     flags=0, mnt_flags=0, name=0xaf037000 "none", data=0xaf036000)
     at namespace.c:626
#6  0xa0050049 in do_mount (dev_name=0xaf037000 "none",
     dir_name=0xaff46000 "/vob/neptune", type_page=0xaf0d8000 "hostfs",
     flags=3236757504, data_page=0xaf036000) at namespace.c:740
#7  0xa0050416 in sys_mount (dev_name=0x8059e20 "none",
     dir_name=0x8059e30 "/vob/neptune", type=0x8059e48 "hostfs",
     flags=3236757504, data=0x8059eb8) at namespace.c:853
#8  0xa00da41c in execute_syscall_tt (r=0xaefc8274) at syscall_kern.c:120
#9  0xa00da4d9 in syscall_handler_tt (sig=12, regs=0xaefc8274)
     at syscall_user.c:37
#10 0xa00db5eb in sig_handler_common_tt (sig=12, sc_ptr=0xaefcbd28)
     at trap_user.c:37
#11 0xa00d7d0d in sig_handler (sig=12, sc=
---Type <return> to continue, or q <return> to quit---
       {gs = 0, __gsh = 0, fs = 0, __fsh = 0, es = 43, __esh = 0, ds = 
43, __dsh = 0, edi = 134586040, esi = 3236757504, ebp = 2684353448, esp 
= 2684353408, ebx = 134585888, edx = 134585928, ecx = 134585904, eax = 
4294967258, trapno = 14, err = 4, eip = 1074791518, cs = 35, __csh = 0, 
eflags = 582, esp_at_signal = 2684353408, ss = 43, __ssh = 0, fpstate = 
0xaefcbd80, oldmask = 134283264, cr2 = 1074791488}) at trap_user.c:101
#12 <signal handler called>
#13 0x4010045e in ?? ()
#14 0x0804a8b8 in ?? ()
#15 0x0804b4d1 in ?? ()
#16 0x0804c125 in ?? ()
#17 0x0804cf1d in ?? ()
#18 0x4002f9a7 in ?? ()


-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML -- new data with memory debugging on

[Jeff Dike]

cfriesen@nortelnetworks.com said:
> I turned on memory debugging, and got the following.  Line 1439 in
> slab.c is 

Excellent.  Can you add the following to hostfs_read_super (not a real patch -
add that line by hand)?

 out_dput:
	dput(sb->s_root);
+	return(NULL);
 out_free:
	kfree(root_dir);

The dput is doing some cleanup for me that I wasn't aware of, including freeing
stuff.

				Jeff



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML -- new data with memory debugging on

[Chris Friesen]

Jeff Dike wrote:
> cfriesen@nortelnetworks.com said:
> 
>>I turned on memory debugging, and got the following.  Line 1439 in
>>slab.c is 
> 
> 
> Excellent.  Can you add the following to hostfs_read_super (not a real patch -
> add that line by hand)?
> 
>  out_dput:
> 	dput(sb->s_root);
> +	return(NULL);
>  out_free:
> 	kfree(root_dir);
> 
> The dput is doing some cleanup for me that I wasn't aware of, including freeing
> stuff.

Looks like that cleaned it up for the minimal setup that was triggering 
the fault.

I'll test it with the full configuration and see how that goes...

Thanks,

Chris

-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com


-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML -- new data with memory debugging on

[Jeff Dike]

cfriesen@nortelnetworks.com said:
> I'll test it with the full configuration and see how that goes... 

I guess things are working OK since you haven't been complaining, but I
thought I make sure.  That fix does make the problem totally go away?

				Jeff



-------------------------------------------------------
This SF.Net email is sponsored by: IBM Linux Tutorials
Free Linux tutorial presented by Daniel Robbins, President and CEO of
GenToo technologies. Learn everything from fundamentals to system
administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML -- new data with memory debugging on

[Chris Friesen]

Jeff Dike wrote:
> cfriesen@nortelnetworks.com said:
> 
>>I'll test it with the full configuration and see how that goes... 
>>
> 
> I guess things are working OK since you haven't been complaining, but I
> thought I make sure.  That fix does make the problem totally go away?

Heh...I meant to get back to you and let you know, but its been kind of 
busy.

Yep, the problems seem to be gone.

I'm not one of the main users of the UML environment, but I haven't 
heard of any more problems from the guys that are.

Chris


-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com



-------------------------------------------------------
This SF.Net email is sponsored by: IBM Linux Tutorials
Free Linux tutorial presented by Daniel Robbins, President and CEO of
GenToo technologies. Learn everything from fundamentals to system
administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

[uml-devel] Re: problems with UML, issues with includes

[Chris Friesen]

Further update on the very strange behaviour I'm seeing.

I instrumented kfree() as mentioned before, and also instrumented 
activate_fd() to test after um_kmalloc() whether the result was already 
in the active_fds list.

I had assumed that I would see it being freed while still on the list, 
then being returned from malloc the next time around, causing a dupe.

However, what I actually saw was


new fd is same address as one already in active_fds
deleting address currently in active_fds


In other words, the um_kmalloc() was returning an address already in the 
active_fds list, *before* an address still in the list had been 
kfree()'d.  The kfree() that I see with an address in the list is the 
one from the out_unlock jump target in activeate_fd().

So somehow um_kmalloc() is returning duplicate addresses without an 
intervening call to kfree().

Any ideas?

Chris




-- 
Chris Friesen                    | MailStop: 043/33/F10
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
Nepean, ON K2H 8E9 Canada        | email: cfriesen@nortelnetworks.com



-------------------------------------------------------
SF.Net is sponsored by: Speed Start Your Linux Apps Now.
Build and deploy apps & Web services for Linux with
a free DVD software kit from IBM. Click Now!
http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel