Hi, On Fri, 2010-03-26 at 13:17 -0700, Jan.Grossmann@xxxxxxxxxxx wrote: > Hello > > The following was done with a vanilla 2.6.34-rc2 kernel. > The bug was not present in 2.6.30.5. ... > [ 0.144012] BUG: unable to handle kernel NULL pointer dereference at > 0000000000000025 > [ 0.148000] IP: [<ffffffff81199c96>] dmar_ir_support+0xb/0x14 > [ 0.148000] PGD 0 > [ 0.148000] Oops: 0000 [#1] SMP > [ 0.148000] last sysfs file: > [ 0.148000] CPU 0 > [ 0.148000] Modules linked in: > [ 0.148000] > [ 0.148000] Pid: 1, comm: swapper Not tainted 2.6.34-rc2 #4 A8N-SLI > Premium/System Product Name > [ 0.148000] RIP: 0010:[<ffffffff81199c96>] [<ffffffff81199c96>] > dmar_ir_support+0xb/0x14 > [ 0.148000] RSP: 0018:ffff88007fbe3e30 EFLAGS: 00010046 > [ 0.148000] RAX: 0000000000000000 RBX: 0000000000000000 RCX: > 000000000000004c > [ 0.148000] RDX: ffffffff81762338 RSI: 0000000000000046 RDI: > 0000000000000010 > [ 0.148000] RBP: ffff88007fbe3e30 R08: 0000000000000002 R09: > 000000000000000a > [ 0.148000] R10: 0000000000000005 R11: 0000000000000000 R12: > 0000000000000010 > [ 0.148000] R13: 0000000000000246 R14: 0000000000000000 R15: > 000000000000e850 > [ 0.148000] FS: 0000000000000000(0000) GS:ffff880001a00000(0000) > knlGS:0000000000000000 > [ 0.148000] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 0.148000] CR2: 0000000000000025 CR3: 0000000001625000 CR4: > 00000000000006f0 > [ 0.148000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: > 0000000000000000 > [ 0.148000] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: > 0000000000000400 > [ 0.148000] Process swapper (pid: 1, threadinfo ffff88007fbe2000, > task ffff88007fbde740) > [ 0.148000] Stack: > [ 0.148000] ffff88007fbe3e40 ffffffff816d1f01 ffff88007fbe3e50 > ffffffff816b7fa6 > [ 0.148000] <0> ffff88007fbe3ea0 ffffffff816b8095 ffff88007fbe3ec0 > ffffffff8130122e > [ 0.148000] <0> ffff880000000008 ffff88007fbe3ed0 ffffffff8168ec20 > 0000000000000200 > [ 0.148000] Call Trace: > [ 0.148000] [<ffffffff816d1f01>] intr_remapping_supported+0x12/0x45 > [ 0.148000] [<ffffffff816b7fa6>] enable_IR+0x9/0x5d > [ 0.148000] [<ffffffff816b8095>] enable_IR_x2apic+0x9b/0x1b6 > [ 0.148000] [<ffffffff8130122e>] ? printk+0x3c/0x3e > [ 0.148000] [<ffffffff816b81f7>] APIC_init_uniprocessor+0x47/0x105 > [ 0.148000] [<ffffffff816b62cf>] native_smp_prepare_cpus+0x190/0x365 > [ 0.148000] [<ffffffff816ab5f5>] kernel_init+0x71/0x1f0 > [ 0.148000] [<ffffffff810097e4>] kernel_thread_helper+0x4/0x10 > [ 0.148000] [<ffffffff816ab584>] ? kernel_init+0x0/0x1f0 > [ 0.148000] [<ffffffff810097e0>] ? kernel_thread_helper+0x0/0x10 > [ 0.148000] Code: ff c7 06 00 00 00 00 48 8b 04 fd 80 ba 42 81 eb 0d > c7 06 02 00 00 00 48 c7 c0 e8 30 4a 81 c9 c3 48 8b 05 0e 4c 56 00 55 48 > 89 e5 <0f> b6 40 25 c9 83 e0 01 c3 55 48 89 e5 e8 7c 8f 16 00 c9 c3 55 > [ 0.148000] RIP [<ffffffff81199c96>] dmar_ir_support+0xb/0x14 > [ 0.148000] RSP <ffff88007fbe3e30> > [ 0.148000] CR2: 0000000000000025 This is interesting because enable_IR_x2apic() will call enable_IR() only when dmar_table_init() was successful. But the oops show dmar_table_init() was successful but later during enable_IR() we see NULL value for dmar_tbl in dmar_ir_support(). Can you please send us your .config and also share if there is anything special with your setup, as we haven't run into a similar problem on a system not supporting intr-remap/x2apic. thanks, suresh -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
