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Re: [microblaze-uclinux] kernel BUG at sched.c:687!
Hi Falk,
My instructions had a mistake. The code must be after SAVE_STATE. If not the
value of r1 is from user stack.
On Thursday 20 April 2006 13:50, Alejandro Lucero wrote:
> On Thursday 20 April 2006 10:31, Brettschneider Falk wrote:
> > Hi,
> >
> > Alejandro Lucero wrote:
> > > I assumed you are using the entry.S without my patch reported
> > > two days ago.
> > > aren't you?
> >
> > I've tried JWs version of your patch but it doesn't help as a bugfix. My
> > environment is one active user app with several threads (SCHED_RR), a
> > high IRQ frequency (about 2 per millisecond), many thread switches, many
> > locks/unlocks of semaphores and mutexes. From time to time one thread of
> > that application calls pthread_cancel() to another thread.
> > Often (about after 20 kill actions) this leads to either a Linux crash
> > (with several versions of "kernel BUG at sched.c:***"), or just a total
> > hang or an exit of the app with return code 5. (The statistical
> > distribution is: displaying of scheduler bug = 0,01%, Linux hang = 60%,
> > process exit = rest.) I haven't the problems if either the IRQ frequency
> > is very low or no threads are cancelled(). That's why I asked you if you
> > ever tried to kill threads in your application, this increases the chance
> > of a Linux crash extremely here.
>
> Perhaps you could do some tests to discard the kernel stack overflow. Try
> to put this in your entry.S file but update the "current" pointer and make
> sure you are not using memory 0x554, 0x558, 0xc64 and 0xc68 (surely LMB
> memory). This code looks at the kernel stack size and if it is greter then
> 0x1d4c (7500bytes) the system will execute an endless loop with interrupts
> disabled. In 0xc64 is stored the maximum kernel stack size used.
>
> Rembember to update current which is my kernel is in 0x0213472c address.
> Use objdump -t image.elf | grep current
>
> Try to put this in ENTRY(irq) just after swi r1, r0, ENTRY_SP and before
> SAVE_STATE
>
> swi r11, r0, 0x554
> swi r12, r0, 0x558
> lwi r11, r0, 0x0213472c;
> addi r11, r11, 0x2000;
> rsub r11, r1, r11;
> lwi r12, r0, 0xc64;
> swi r11, r0, 0xc68;
> rsub r11, r11, r12;
> bgei r11, 1f;
> lwi r11, r0, 0xc68;
> swi r11, r0, 0xc64;
> 1:
> lwi r11, r0, 0x0213472c;
> addi r11, r11, 0x2000;
> rsub r11, r1, r11;
> addi r12, r0, 0x1d4c;
> rsub r11, r12, r11;
> blei r11, 2f;
> lwi r11, r0, 0;
> mts rmsr, r11;
> nop;
> nop;
> nop;
> bri -8;
> 2:
> lwi r11, r0, 0x554
> lwi r12, r0, 0x558
>
> > Cheers, F@lk
> > ___________________________
> > microblaze-uclinux mailing list
> > microblaze-uclinux@xxxxxxxxxxxxxx
> > Project Home Page : http://www.itee.uq.edu.au/~jwilliams/mblaze-uclinux
> > Mailing List Archive :
> > http://www.itee.uq.edu.au/~listarch/microblaze-uclinux/
--
Alejandro Lucero
Technical Director
+34 665 68 71 68
Valencia (SPAIN)
www.os3sl.com
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