[uml-devel] SKAS-v8: RC5 released against 2.6.7 - 2.6.11 kernels

[uml-devel] SKAS-v8: RC5 released against 2.6.7 - 2.6.11 kernels

[Blaisorblade]

This time, I've announced this on my homepage, since I'd like to get a lot 
more testing and to release this patch unchanged as -V8 final version.

Things I've forgot:
* make it apply easily on Fedora kernels.

This should simply mean moving the TIF_SYSCALL_EMU to place no.8, to leave a 
slot free for _DB7, needed for 4g4g or something like that and using testw 
instead of testb for testing against it. This will be done in -V9.

The summary of changes against -RC2 is short... I dropped 
fix-dumpable-handling because I don't feel it secure yet, so everybody using 
-RC2 should upgrade.

The problem is that the correct locking is difficult and even mainline kernel 
code has a lot of confusion about it, and I want to sort this out first, to 
avoid problems with the patch.

Sorry Michael, but this is lower priority than stability and security. It will 
be for next patch.

Description of this patch.
* fix-dumpable-handling.patch: this implemented a feature / bug fix requested 
by Michael Richardson <mcr@sandelman.ottawa.on.ca>. I.e., with this, in 
normal cases, UML *is* allowed to dump core and be seen inside /proc - (until 
now it was treated as if it was a setuid process or one which changed UID / 
GID). If I did any error, however, it could allow privilege escalation.

-- 
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729
http://www.user-mode-linux.org/~blaisorblade





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[uml-devel] Re: [uml-user] Loadav always >1.0 (2.6.X)

[Blaisorblade]

[-- Attachment #1: Type: text/plain, Size: 2129 bytes --]

On Tuesday 19 April 2005 18:36, Daniel Tombeil wrote:
> Hi Blaisorblade,
>
> On Thu, 2005-04-14 at 23:11 +0200, Blaisorblade wrote:
> > On Thursday 14 April 2005 20:36, Daniel Tombeil wrote:
> > > Hello,
>
> [...]
>
> > discussed patch which fixed it. I'd like to know any info on this road
> > (it's possible that these two bugs are just similar, but entirely
> > different, but I'd like some reports).
> >
> > Also I'm currently in short of time, so I cannot investigate this well...
>
> sorry, I don't seem to unterstand. I searched the devel list archive
> (I'm not subscribed to devel) and found the thread on the change
> from /proc/stat. I can confirm that my problem seems to be related. But
> I wasn't able to extract the info which patch should solve the problem.

The patch I suggested to Chris was named, in the patch, 
"update-process-times", however the name in my tree was uml-timer-context. 
I've attached it.

Chris Aker reported that in 2.6.10 it fixed the problem, but I didn't verify 
(even because I simply knew that patch *had* to be applied to fix some 
problems, so I just asked it to check that it fixed also that problem). Also, 
this patch *has* been applied in 2.6.11; however, I'd still like a 
confirmation that it fixed the problem in 2.6.10.

That said, I'm currently running and verifying this on 2.6.11 and what I see 
with top is that

a) ksoftirqd is always runnable, but
b) it always gets 0% cpu usage
which is *very* strange.

While on 2.6.9 it works perfectly ok.
> I tried all of your -bb and -bs from 2.6.10 to 2.6.11.7 with the same
> result on load 1.0. Beside of that the kernels seem to be very stable.
> I'm running 5 Guest UMLs with Mailserver (exim,spamassasin,clamav deb-
> sarge), WWW (lamp, deb-sarge), Aptcache (squid, deb-sarge), 2 UMLs for
> friends (LAMP, Mail, deb-sarge) on an 2.6.8skas-v6 Host (deb-sarge). I
> now went back to a 2.4.27-bs1 which seems to be rock-solid because some
> of the friends didn't like the 1.0 load in their stats or something :)
-- 
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729
http://www.user-mode-linux.org/~blaisorblade

[-- Attachment #2: uml-timer-context.patch --]
[-- Type: text/x-diff, Size: 1045 bytes --]


From: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
From: Bodo Stroesser <bstroesser@fujitsu-siemens.com>

In call to update_process_times() set parameter user
correctly. (was from for SKAS).

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
---

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

 vanilla-linux-2.6.9-paolo/arch/um/kernel/time_kern.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

diff -puN arch/um/kernel/time_kern.c~uml-timer-context arch/um/kernel/time_kern.c
--- vanilla-linux-2.6.9/arch/um/kernel/time_kern.c~uml-timer-context	2004-12-01 18:04:36.967383992 +0100
+++ vanilla-linux-2.6.9-paolo/arch/um/kernel/time_kern.c	2004-12-01 18:04:36.971383384 +0100
@@ -171,7 +171,7 @@ void timer_handler(int sig, union uml_pt
 {
 #ifdef CONFIG_SMP
 	local_irq_disable();
-	update_process_times(user_context(UPT_SP(regs)));
+	update_process_times(CHOOSE_MODE(user_context(UPT_SP(regs)), (regs)->skas.is_user));
 	local_irq_enable();
 #endif
 	if(current_thread->cpu == 0)
_