[patch 1/1] uml: fix lvalue for gcc4

[patch 1/1] uml: fix lvalue for gcc4

[blaisorblade]

This construct is refused by GCC 4, so here's the fix.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
---

 linux-2.6.git-paolo/arch/um/sys-x86_64/signal.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

diff -puN arch/um/sys-x86_64/signal.c~uml-fix-for-gcc4-lvalue arch/um/sys-x86_64/signal.c
--- linux-2.6.git/arch/um/sys-x86_64/signal.c~uml-fix-for-gcc4-lvalue	2005-07-09 13:01:03.000000000 +0200
+++ linux-2.6.git-paolo/arch/um/sys-x86_64/signal.c	2005-07-09 13:01:03.000000000 +0200
@@ -168,7 +168,7 @@ int setup_signal_stack_si(unsigned long 
 
 	frame = (struct rt_sigframe __user *)
 		round_down(stack_top - sizeof(struct rt_sigframe), 16) - 8;
-	((unsigned char *) frame) -= 128;
+	frame -= 128 / sizeof(frame);
 
 	if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
 		goto out;
_

Re: [patch 1/1] uml: fix lvalue for gcc4

[Russell King]

On Sat, Jul 09, 2005 at 01:01:33PM +0200, blaisorblade@yahoo.it wrote:
> diff -puN arch/um/sys-x86_64/signal.c~uml-fix-for-gcc4-lvalue arch/um/sys-x86_64/signal.c
> --- linux-2.6.git/arch/um/sys-x86_64/signal.c~uml-fix-for-gcc4-lvalue	2005-07-09 13:01:03.000000000 +0200
> +++ linux-2.6.git-paolo/arch/um/sys-x86_64/signal.c	2005-07-09 13:01:03.000000000 +0200
> @@ -168,7 +168,7 @@ int setup_signal_stack_si(unsigned long 
>  
>  	frame = (struct rt_sigframe __user *)
>  		round_down(stack_top - sizeof(struct rt_sigframe), 16) - 8;
> -	((unsigned char *) frame) -= 128;
> +	frame -= 128 / sizeof(frame);

Are you sure these two are identical?

The above code fragment looks suspicious anyway, particularly:

 	frame = (struct rt_sigframe __user *)
 		round_down(stack_top - sizeof(struct rt_sigframe), 16) - 8;

which will put the frame at 8 * sizeof(struct rt_sigframe) below
the point which round_down() would return (which would be 1 struct
rt_sigframe below stack_top, rounded down).

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core

unregister_netdevice: waiting for tap24 to become free

[Peter]

Hi.  I am hitting a bug that manifests in an unregister_netdevice error 
message.  After the problem is triggered processes like ifconfig, tunctl 
and route refuse to exit, even with killed.  And the only solution I 
have found to regaining control of the server is issuing a reboot.

The server is running a number of tap devices.  (It is a UML host server 
running the skas patches http://www.user-mode-linux.org/~blaisorblade/).

Regards, Peter

# uname -r
2.6.11.7-skas3-v8

unregister_netdevice: waiting for tap24 to become free. Usage count = 1
unregister_netdevice: waiting for tap24 to become free. Usage count = 1
unregister_netdevice: waiting for tap24 to become free. Usage count = 1
unregister_netdevice: waiting for tap24 to become free. Usage count = 1
unregister_netdevice: waiting for tap24 to become free. Usage count = 1
unregister_netdevice: waiting for tap24 to become free. Usage count = 1
unregister_netdevice: waiting for tap24 to become free. Usage count = 1


30684 ?        DW     0:45          \_ [tunctl]
31974 ?        S      0:00 /bin/bash ./monitorbw.sh
31976 ?        S      0:00  \_ /bin/bash ./monitorbw.sh
31978 ?        D      0:00      \_ /sbin/ifconfig
31979 ?        S      0:00      \_ grep \(tap\)\|\(RX bytes\)
32052 ?        S      0:00 /bin/bash /opt/uml/umlcontrol.sh start --user 
gildersleeve.de
32112 ?        S      0:00  \_ /bin/bash /opt/uml/umlrun.sh --user 
gildersleeve.de
32152 ?        S      0:00      \_ /bin/bash ./umlnetworksetup.sh 
--check --user gildersleeve.de
32176 ?        D      0:00          \_ tunctl -u gildersleeve.de -t tap24

Re: [uml-devel] Re: [patch 1/1] uml: fix lvalue for gcc4

[Blaisorblade]

On Saturday 09 July 2005 13:07, Russell King wrote:
> On Sat, Jul 09, 2005 at 01:01:33PM +0200, blaisorblade@yahoo.it wrote:
> > diff -puN arch/um/sys-x86_64/signal.c~uml-fix-for-gcc4-lvalue
> > arch/um/sys-x86_64/signal.c ---
> > linux-2.6.git/arch/um/sys-x86_64/signal.c~uml-fix-for-gcc4-lvalue	2005-07
> >-09 13:01:03.000000000 +0200 +++
> > linux-2.6.git-paolo/arch/um/sys-x86_64/signal.c	2005-07-09
> > 13:01:03.000000000 +0200 @@ -168,7 +168,7 @@ int
> > setup_signal_stack_si(unsigned long
> >
> >  	frame = (struct rt_sigframe __user *)
> >  		round_down(stack_top - sizeof(struct rt_sigframe), 16) - 8;
> > -	((unsigned char *) frame) -= 128;
> > +	frame -= 128 / sizeof(frame);
>
> Are you sure these two are identical?
SOOOOOOOOORRY, I've become crazy, I meant sizeof(*frame)... thanks for 
noticing.

> The above code fragment looks suspicious anyway, particularly:
>
>  	frame = (struct rt_sigframe __user *)
>  		round_down(stack_top - sizeof(struct rt_sigframe), 16) - 8;
>
> which will put the frame at 8 * sizeof(struct rt_sigframe) below
> the point which round_down() would return (which would be 1 struct
> rt_sigframe below stack_top, rounded down).

You're completely right.

The code is copied from arch/x86_64/kernel/signal.c:setup_rt_frame(), so it 
should make some sense; but in the source, the cast is to (void*).

Surely Jeff, seeing that the result is assigned to a struct rt_sigframe 
__user, "fixed" it. The line I'm patching is new from Jeff, and I don't know 
what's about (I just remember that 

Also, the below access_ok() called on fp (which is still NULL) is surely 
completely wrong, though it won't fail (after all, NULL is under TASK_SIZE. 
right?).

On x86_64 the code is always used from arch/um/kernel/signal_kern.c, since 
CONFIG_whatever is not enabled.
-- 
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade


	

	
		
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Re: [uml-devel] unregister_netdevice: waiting for tap24 to become free

[Blaisorblade]

On Monday 11 July 2005 21:12, Peter wrote:
> Hi.  I am hitting a bug that manifests in an unregister_netdevice error
> message.  After the problem is triggered processes like ifconfig, tunctl
> and route refuse to exit, even with killed.
Even from the "D" state below, it's clear that there was a deadlock on some 
semaphore, related to tap24... Could you search your kernel logs for traces 
of an Oops?
> And the only solution I 
> have found to regaining control of the server is issuing a reboot.

> The server is running a number of tap devices.  (It is a UML host server
> running the skas patches http://www.user-mode-linux.org/~blaisorblade/).
>
> Regards, Peter
>
> # uname -r
> 2.6.11.7-skas3-v8
>
> unregister_netdevice: waiting for tap24 to become free. Usage count = 1
> unregister_netdevice: waiting for tap24 to become free. Usage count = 1
> unregister_netdevice: waiting for tap24 to become free. Usage count = 1
> unregister_netdevice: waiting for tap24 to become free. Usage count = 1
> unregister_netdevice: waiting for tap24 to become free. Usage count = 1
> unregister_netdevice: waiting for tap24 to become free. Usage count = 1
> unregister_netdevice: waiting for tap24 to become free. Usage count = 1
>
>
> 30684 ?        DW     0:45          \_ [tunctl]
> 31974 ?        S      0:00 /bin/bash ./monitorbw.sh
> 31976 ?        S      0:00  \_ /bin/bash ./monitorbw.sh
> 31978 ?        D      0:00      \_ /sbin/ifconfig
> 31979 ?        S      0:00      \_ grep \(tap\)\|\(RX bytes\)
> 32052 ?        S      0:00 /bin/bash /opt/uml/umlcontrol.sh start --user
> gildersleeve.de
> 32112 ?        S      0:00  \_ /bin/bash /opt/uml/umlrun.sh --user
> gildersleeve.de
> 32152 ?        S      0:00      \_ /bin/bash ./umlnetworksetup.sh
> --check --user gildersleeve.de
> 32176 ?        D      0:00          \_ tunctl -u gildersleeve.de -t tap24
>
>
> -------------------------------------------------------
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-- 
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade

		
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Re: unregister_netdevice: waiting for tap24 to become free

[Peter]

Nothing in the logs prior to the first error message.

I've hit this before at different times on other servers.  If there are 
some commands I can run to gather more diagnostics on the problem, 
please let me know and I'll capture more information next time.

I see the error was reported with older 2.6 kernels and a patch was 
floating around.  I'm not sure if that is integrated into the current 
2.6.11 kernel. 
http://www.google.com/search?q=unregister_netdevice%3A+waiting

Regards, Peter

Jul 10 16:52:03 host39 sshd(pam_unix)[19779]: authentication failure; 
logname= uid=0 euid=0 tty=ssh ruser= rhost=140.123.23.77  user=halt
Jul 10 16:52:07 host39 sshd(pam_unix)[19781]: check pass; user unknown
Jul 10 16:52:07 host39 sshd(pam_unix)[19781]: authentication failure; 
logname= uid=0 euid=0 tty=ssh ruser= rhost=140.123.23.77
Jul 11 12:04:04 host39 kernel: unregister_netdevice: waiting for tap24 
to become free. Usage count = 1


Blaisorblade wrote:
> On Monday 11 July 2005 21:12, Peter wrote:
> 
>>Hi.  I am hitting a bug that manifests in an unregister_netdevice error
>>message.  After the problem is triggered processes like ifconfig, tunctl
>>and route refuse to exit, even with killed.
> 
> Even from the "D" state below, it's clear that there was a deadlock on some 
> semaphore, related to tap24... Could you search your kernel logs for traces 
> of an Oops?
> 
>>And the only solution I 
>>have found to regaining control of the server is issuing a reboot.
> 
> 
>>The server is running a number of tap devices.  (It is a UML host server
>>running the skas patches http://www.user-mode-linux.org/~blaisorblade/).
>>
>>Regards, Peter
>>
>># uname -r
>>2.6.11.7-skas3-v8
>>
>>unregister_netdevice: waiting for tap24 to become free. Usage count = 1
>>unregister_netdevice: waiting for tap24 to become free. Usage count = 1
>>unregister_netdevice: waiting for tap24 to become free. Usage count = 1
>>unregister_netdevice: waiting for tap24 to become free. Usage count = 1
>>unregister_netdevice: waiting for tap24 to become free. Usage count = 1
>>unregister_netdevice: waiting for tap24 to become free. Usage count = 1
>>unregister_netdevice: waiting for tap24 to become free. Usage count = 1
>>
>>
>>30684 ?        DW     0:45          \_ [tunctl]
>>31974 ?        S      0:00 /bin/bash ./monitorbw.sh
>>31976 ?        S      0:00  \_ /bin/bash ./monitorbw.sh
>>31978 ?        D      0:00      \_ /sbin/ifconfig
>>31979 ?        S      0:00      \_ grep \(tap\)\|\(RX bytes\)
>>32052 ?        S      0:00 /bin/bash /opt/uml/umlcontrol.sh start --user
>>gildersleeve.de
>>32112 ?        S      0:00  \_ /bin/bash /opt/uml/umlrun.sh --user
>>gildersleeve.de
>>32152 ?        S      0:00      \_ /bin/bash ./umlnetworksetup.sh
>>--check --user gildersleeve.de
>>32176 ?        D      0:00          \_ tunctl -u gildersleeve.de -t tap24
>>

Re: unregister_netdevice: waiting for tap24 to become free

[Blaisorblade]

On Tuesday 12 July 2005 00:26, Peter wrote:
> Nothing in the logs prior to the first error message.
>
> I've hit this before at different times on other servers.  If there are
> some commands I can run to gather more diagnostics on the problem,
> please let me know and I'll capture more information next time.
>
> I see the error was reported with older 2.6 kernels and a patch was
> floating around.  I'm not sure if that is integrated into the current
> 2.6.11 kernel.
The patch named there has been integrated, verifyable at 
http://linux.bkbits.net:8080/linux-2.6/cset@4129735fMSVl0_RA4uNcNBWHFjT-zw

However this time the bug is probably due to something entirely different, the 
message is not very specific.

Tried 2.6.12? SKAS has been already updated (plus there's an important update 
for SKAS, from -V8 to -V8.2).
> http://www.google.com/search?q=unregister_netdevice%3A+waiting
>
> Regards, Peter

-- 
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade

	

	
		
___________________________________ 
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Re: [uml-devel] Re: unregister_netdevice: waiting for tap24 to become free

[Peter]

I just tried 2.6.12.2 with skas-V8.2.  The server (otherwise reliable), 
had a kernel crash (which I was unable to capture) within a couple of 
hours of boot up.

Regards, Peter

Blaisorblade wrote:
> On Tuesday 12 July 2005 00:26, Peter wrote:
> 
>>Nothing in the logs prior to the first error message.
>>
>>I've hit this before at different times on other servers.  If there are
>>some commands I can run to gather more diagnostics on the problem,
>>please let me know and I'll capture more information next time.
>>
>>I see the error was reported with older 2.6 kernels and a patch was
>>floating around.  I'm not sure if that is integrated into the current
>>2.6.11 kernel.
> 
> The patch named there has been integrated, verifyable at 
> http://linux.bkbits.net:8080/linux-2.6/cset@4129735fMSVl0_RA4uNcNBWHFjT-zw
> 
> However this time the bug is probably due to something entirely different, the 
> message is not very specific.
> 
> Tried 2.6.12? SKAS has been already updated (plus there's an important update 
> for SKAS, from -V8 to -V8.2).
> 
>>http://www.google.com/search?q=unregister_netdevice%3A+waiting
>>
>>Regards, Peter
> 
>