Ok, forget it all. It crashed again. :) Must be nvidia... Quoting Michael Buesch : > Quoting Ingo Molnar : > > > > * Michael Buesch wrote: > > > > > > > The two attached patches (one against vanilla kernel and one > > > > > against ck patchset) moves the rq-lock a few lines up in > > > > > scheduler_tick() to also protect set_tsk_need_resched(). > > > > > > > > > > Is that neccessary? > > > > > > > > scheduler_tick() is a special case, 'current' is pinned and cannot > > > > go away, nor can it get off the runqueue. > > > > > > Can you explain in short, why this is the case, please? I don't really > > > get behind it. How are the two things enforced? > > > > 'current' is the currently executing task and as such it wont get moved > > off the runqueue. The only way to leave the runqueue is to execute > > schedule() [or to be preempted]. > > Ok, I understand that. > > Someone else said to me: > [quote] > "another runqueue might want to touch your runqueue > while you're in scheduler_tick" ... > "that is far more likely to hit with many many cpus and I'd > be surprised if you're the first person to get a race there" > [/quote] > > What about this? Is this possible? Or did she/he/it miss a point? > > > It's this scenario here: > I frequently get oopses in cpu_idle(). In the two hours before > I made the patch, the machine hung twice. Since I'm running > a patched scheduler, It did not hang again. I gave em about > 15 hours testing. > > But maybe that's all pure luck. > > > Ingo > > > Unable to handle kernel paging request at virtual address 00099108 > printing eip: > b01010c0 > *pde = 00000000 > Oops: 0000 [#1] > SMP > Modules linked in: nfs lockd sunrpc nvidia ipv6 ohci_hcd tuner tvaudio msp3400 bttv video_buf firmware_class btcx_risc ehci_hcd uhci_hcd usbcore intel_agp agpgart evdev > CPU: 0 > EIP: 0060:[] Tainted: P VLI > EFLAGS: 00010286 (2.6.10-rc2-ck2-nozeroram-findvmastat) > EIP is at cpu_idle+0x31/0x3f > eax: 00000001 ebx: 00099100 ecx: 00000000 edx: 0000001d > esi: 00000000 edi: b03dff9c ebp: b03dffe4 esp: b03dffe0 > ds: 007b es: 007b ss: 0068 > Process swapper (pid: 0, threadinfo=b03de000 task=b034db40) > Stack: 00020800 b03dfff8 b03e0898 000000bd b03e0340 b040cb80 0044f007 b0100211 > Call Trace: > [] show_stack+0x7a/0x90 > [] show_registers+0x152/0x1ca > [] die+0xf4/0x178 > [] do_page_fault+0x42a/0x645 > [] error_code+0x2b/0x30 > [] start_kernel+0x13a/0x151 > [] 0xb0100211 > Code: e0 ff ff 21 e3 eb 24 8b 0d 84 c6 40 b0 b8 26 10 10 b0 8b 15 c0 eb 34 b0 85 c9 0f 44 c8 8b 43 10 c1 e0 07 89 90 84 52 41 b0 ff d1 <8b> 43 08 a8 08 74 d5 e8 d8 7f 1f 00 eb f2 55 89 e5 56 53 fb ba > <0>Kernel panic - not syncing: Attempted to kill the idle task! > > > b010108f : > b010108f: 55 push %ebp > b0101090: 89 e5 mov %esp,%ebp > b0101092: 53 push %ebx > b0101093: bb 00 e0 ff ff mov $0xffffe000,%ebx > b0101098: 21 e3 and %esp,%ebx > b010109a: eb 24 jmp b01010c0 > b010109c: 8b 0d 84 c6 40 b0 mov 0xb040c684,%ecx > b01010a2: b8 26 10 10 b0 mov $0xb0101026,%eax > b01010a7: 8b 15 c0 eb 34 b0 mov 0xb034ebc0,%edx > b01010ad: 85 c9 test %ecx,%ecx > b01010af: 0f 44 c8 cmove %eax,%ecx > b01010b2: 8b 43 10 mov 0x10(%ebx),%eax > b01010b5: c1 e0 07 shl $0x7,%eax > b01010b8: 89 90 84 52 41 b0 mov %edx,0xb0415284(%eax) > b01010be: ff d1 call *%ecx > b01010c0: 8b 43 08 mov 0x8(%ebx),%eax > ^^^^^^^^^^^^^^^^^^ OOPS. This is the check to need_resched(). > b01010c3: a8 08 test $0x8,%al > b01010c5: 74 d5 je b010109c > b01010c7: e8 d8 7f 1f 00 call b02f90a4 > b01010cc: eb f2 jmp b01010c0 > > > Ah, and yes, the kernel is tainted. So Nvidia already received a bugreport. > -- Regards Michael Buesch [ http://www.tuxsoft.de.vu ]