<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-7" http-equiv="Content-Type"> </head> <body bgcolor="#ffffff" text="#000000"> Dear Fedora users, I have an AMD-64 system which I have 32-bit fedora installed. The system was working perfectly with fedora core 4. When core 5 was released, I upgraded again to the 32-bit version. Since day one, I experienced random freezes. So, I did a clean install of 32-bit core 5. The freezes didn't stop. I get them so frequently, that it is impossible to work with the system. My system is in this state quite many months now (this means that I don't use it at all). I have tried to ask for help in this list on how to debug the freezes, but with no results. Of course I have tried to check my hardware, so I did a memtest86 check on memory and a SMART check on my (only) disk. I even changed the graphics card. No hardware errors have been found but the problem persisted. Today, I came across a kernel boot argument that can help debug such freezes nmi_watchdog=1. So, I booted my system with this option, and I haven't yet got a freeze (so I added permenantly in my grub.conf :-)) Looking in the output of dmesg, I can see strange entries, like the one at the end of this mail. Is there a problem with the cpuspeed process? Is it safe to disable it? What is its job? Is there anything I can set in my BIOS to prevent this? Finally, is it a bug that should be reported somewhere? (I have never reported a bug using bugzilla :-)) Any help will be welcomed :-) Regards, George BUG: unable to handle kernel NULL pointer dereference at virtual address 00000000 printing eip: c040b8bf *pde = 00000000 Oops: 0000 [#1] last sysfs file: /devices/system/cpu/cpu0/cpufreq/scaling_setspeed Modules linked in: autofs4 sunrpc ip_conntrack_ftp ip_conntrack_netbios_ns ipt_REJECT xt_state ip_conntrack nfnetlink xt_tcpudp iptable_filter ip_tables x_tables dm_mirror dm_mod video button battery ac ipv6 lp parport_pc parport nvidia(U) floppy ehci_hcd ohci_hcd r8169 forcedeth i2c_nforce2 i2c_core ext3 jbd sata_nv libata sd_mod scsi_mod CPU: 0 EIP: 0060:[<c040b8bf>] Tainted: P VLI EFLAGS: 00010246 (2.6.17-1.2139_FC5 #1) EIP is at powernowk8_target+0x4fb/0x742 eax: 00000000 ebx: 00000008 ecx: c0010042 edx: 00000006 esi: f7e7e5c0 edi: 00000000 ebp: 0000000a esp: f41e9e9c ds: 007b es: 007b ss: 0068 Process cpuspeed (pid: 1239, threadinfo=f41e9000 task=f3c3faa0) Stack: 00000002 c06197f5 c0619d0e 00000000 0000000c 00000006 00000000 00000002 000c3500 f7e31200 0000000c 00000002 00000006 0000000a 00000000 001e8480 000c3500 c0600f00 00000002 c040b3c4 f7e31200 00000000 000c3500 c059de73 Call Trace: <c0600f00> __mutex_lock_slowpath+0x262/0x439 <c040b3c4> powernowk8_target+0x0/0x742 <c059de73> __cpufreq_driver_target+0x52/0x61 <c059ee1f> store_speed+0xab/0xc0 <c059ed74> store_speed+0x0/0xc0 <c059d2d3> store+0x31/0x41 <c04957c0> sysfs_write_file+0xa6/0xcc <c049571a> sysfs_write_file+0x0/0xcc <c045c597> vfs_write+0xa8/0x150 <c045cacb> sys_write+0x41/0x67 <c0402cb3> syscall_call+0x7/0xb Code: f8 ff ff 85 c0 0f 85 bb 01 00 00 8b 46 28 39 f8 74 19 89 7c 24 08 89 44 24 04 c7 04 24 4e 9d 61 c0 e8 09 11 01 00 e9 9b 01 00 00 <8b> 46 24 39 44 24 30 74 15 89 44 24 08 8b 44 24 30 c7 04 24 99 EIP: [<c040b8bf>] powernowk8_target+0x4fb/0x742 SS:ESP 0068:f41e9e9c BUG: cpuspeed/1239, lock held at task exit time! [c06dfe80] {userspace_mutex} .. held by: cpuspeed: 1239 [f3c3faa0, 115] ... acquired at: store_speed+0x6b/0xc0 </body> </html>