I looked around on the MLs for mention of this, but didn't find anything that appeared to match.
Platform: HP rx8620 - 16-cpu/32GB/4-node ia64 [Madison] 2.6.23-rc7-mm1 broken out -- panic occurs when git-sched.patch pushed: Unable to handle kernel NULL pointer dereference (address 0000000000000000) swapper[0]: Oops 8813272891392 [1] Modules linked in: scsi_wait_scan ehci_hcd ohci_hcd uhci_hcd usbcore Pid: 0, CPU 14, comm: swapper psr : 0000101008522030 ifs : 8000000000000002 ip : [<a0000001003014e0>] Not tainted ip is at rb_next+0x0/0x140 unat: 0000000000000000 pfs : 0000000000000308 rsc : 0000000000000003 rnat: 8000000000000012 bsps: 000000000001003e pr : 6609a840599519a5 ldrs: 0000000000000000 ccv : 0000000000000002 fpsr: 0009804c8a70433f csd : 0000000000000000 ssd : 0000000000000000 b0 : a000000100078dc0 b6 : a000000100074a40 b7 : a000000100078e00 f6 : 1003e0000000000000000 f7 : 1003e0000000000400000 f8 : 1003e000000002aaaaaab f9 : 1003e0000000d43798a2b f10 : 1003e35e9970b967dd8b9 f11 : 1003e0000000000000002 r1 : a000000100bc0920 r2 : e0000760000577f0 r3 : e000076000057f10 r8 : fffffffffffffff0 r9 : 0000000000000002 r10 : e000076000057780 r11 : 0000000000000000 r12 : e00007004160fe10 r13 : e000070041608000 r14 : 0000000000000000 r15 : 000000000000000e r16 : 00000007f6c30a22 r17 : e000070041608040 r18 : a0000001008383a8 r19 : a000000100078e00 r20 : e000076000055bb8 r21 : e000076000055bb0 r22 : e000076000057ed0 r23 : 00000000000f4240 r24 : a0000001009e0440 r25 : e000070041608bb4 r26 : 0000000000000000 r27 : 0000000000000000 r28 : e000076000057f80 r29 : 00000000000002e7 r30 : 0000000000000000 r31 : e000076000057780 Call Trace: [<a000000100014f60>] show_stack+0x80/0xa0 sp=e00007004160f9e0 bsp=e000070041609008 [<a000000100015bf0>] show_regs+0x870/0x8a0 sp=e00007004160fbb0 bsp=e000070041608fa8 [<a00000010003d170>] die+0x190/0x300 sp=e00007004160fbb0 bsp=e000070041608f60 [<a000000100071bc0>] ia64_do_page_fault+0x780/0xa80 sp=e00007004160fbb0 bsp=e000070041608f08 [<a00000010000b5c0>] ia64_leave_kernel+0x0/0x270 sp=e00007004160fc40 bsp=e000070041608f08 [<a0000001003014e0>] rb_next+0x0/0x140 sp=e00007004160fe10 bsp=e000070041608ef8 [<a000000100078dc0>] __dequeue_entity+0x80/0xc0 sp=e00007004160fe10 bsp=e000070041608ec8 [<a000000100078e60>] pick_next_task_fair+0x60/0x180 sp=e00007004160fe10 bsp=e000070041608e98 [<a0000001006a5880>] schedule+0x340/0x19c0 sp=e00007004160fe10 bsp=e000070041608cc0 [<a000000100014cb0>] cpu_idle+0x290/0x3e0 sp=e00007004160fe30 bsp=e000070041608c50 [<a000000100066020>] start_secondary+0x380/0x5a0 sp=e00007004160fe30 bsp=e000070041608c00 [<a0000001006abca0>] __kprobes_text_end+0x6c0/0x6f0 sp=e00007004160fe30 bsp=e000070041608c00 Taking a quick look at [__]{en|de|queue_entity() and the functions they call, I see something suspicious in set_leftmost() in sched_fair.c: static inline void set_leftmost(struct cfs_rq *cfs_rq, struct rb_node *leftmost) { struct sched_entity *se; cfs_rq->rb_leftmost = leftmost; if (leftmost) se = rb_entry(leftmost, struct sched_entity, run_node); } Missing code? corrupt patch? config available on request, but there doesn't seem to be much in the way of scheduler config option. A few that might apply: SCHED_SMT is not set SCHED_DEBUG=y SCHEDSTATS=y Regards, Lee Schermerhorn - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/