2.6.0-test4: Unable to handle kernel NULL pointer dereference

2.6.0-test4: Unable to handle kernel NULL pointer dereference

[Christopher Swingley]

Greetings!

I don't know if this sort of thing qualifies as a bug of interest, but I 
was able to get this four times in the space of a half an hour while 
trying to 'apt-get dist-upgrade' my system.  

Thanks for taking a look!

Here's the kernel log:

kernel: Unable to handle kernel NULL pointer dereference at virtual address 00000000
kernel:  printing eip:
kernel: c016511a
kernel: *pde = 00000000
kernel: Oops: 0000 [#1]
kernel: CPU:    0
kernel: EIP:    0060:[find_inode_fast+26/96]    Not tainted
kernel: EFLAGS: 00010282
kernel: EIP is at find_inode_fast+0x1a/0x60
kernel: eax: c0600610   ebx: 0005a648   ecx: 0000000f   edx: 00000000
kernel: esi: de944e00   edi: c153f9fc   ebp: c2cb9e28   esp: c2cb9e18
kernel: ds: 007b   es: 007b   ss: 0068
kernel: Process dpkg (pid: 5114, threadinfo=c2cb8000 task=de247280)
kernel: Stack: d8d06240 c2cb8000 c41aa140 0005a648 c2cb9e4c c01657a0 de944e00 c153f9fc
kernel:        0005a648 c153f9fc 0005a648 c41aa140 de944e00 c2cb9e6c c0189242 de944e00
kernel:        0005a648 d8cfe338 fffffff4 d8d1ea38 d8d1e9d0 c2cb9e90 c0159980 d8d1e9d0
kernel: Call Trace:
kernel:  [iget_locked+80/208] iget_locked+0x50/0xd0
kernel:  [ext3_lookup+98/192] ext3_lookup+0x62/0xc0
kernel:  [real_lookup+192/240] real_lookup+0xc0/0xf0
kernel:  [do_lookup+134/160] do_lookup+0x86/0xa0
kernel:  [link_path_walk+1169/2336] link_path_walk+0x491/0x920
kernel:  [open_namei+135/1008] open_namei+0x87/0x3f0
kernel:  [filp_open+65/112] filp_open+0x41/0x70
kernel:  [sys_open+83/144] sys_open+0x53/0x90
kernel:  [syscall_call+7/11] syscall_call+0x7/0xb
kernel:
kernel: Code: 0f 18 02 90 39 58 18 74 10 85 d2 89 d0 75 ef 31 c0 83 c4 04
kernel:  <6>note: dpkg[5114] exited with preempt_count 1
kernel: bad: scheduling while atomic!
kernel: Call Trace:
kernel:  [schedule+954/960] schedule+0x3ba/0x3c0
kernel:  [unmap_page_range+65/112] unmap_page_range+0x41/0x70
kernel:  [unmap_vmas+433/544] unmap_vmas+0x1b1/0x220
kernel:  [exit_mmap+121/400] exit_mmap+0x79/0x190
kernel:  [mmput+102/192] mmput+0x66/0xc0
kernel:  [do_exit+297/832] do_exit+0x129/0x340
kernel:  [die+225/240] die+0xe1/0xf0
kernel:  [do_page_fault+348/1167] do_page_fault+0x15c/0x48f
kernel:  [ext3_getblk+149/624] ext3_getblk+0x95/0x270
kernel:  [wake_up_buffer+17/48] wake_up_buffer+0x11/0x30
kernel:  [unlock_buffer+53/80] unlock_buffer+0x35/0x50
kernel:  [ll_rw_block+66/144] ll_rw_block+0x42/0x90
kernel:  [__ext3_journal_stop+36/80] __ext3_journal_stop+0x24/0x50
kernel:  [ext3_find_entry+650/960] ext3_find_entry+0x28a/0x3c0
kernel:  [do_page_fault+0/1167] do_page_fault+0x0/0x48f
kernel:  [error_code+45/56] error_code+0x2d/0x38
kernel:  [find_inode_fast+26/96] find_inode_fast+0x1a/0x60
kernel:  [iget_locked+80/208] iget_locked+0x50/0xd0
kernel:  [ext3_lookup+98/192] ext3_lookup+0x62/0xc0
kernel:  [real_lookup+192/240] real_lookup+0xc0/0xf0
kernel:  [do_lookup+134/160] do_lookup+0x86/0xa0
kernel:  [link_path_walk+1169/2336] link_path_walk+0x491/0x920
kernel:  [open_namei+135/1008] open_namei+0x87/0x3f0
kernel:  [filp_open+65/112] filp_open+0x41/0x70
kernel:  [sys_open+83/144] sys_open+0x53/0x90
kernel:  [syscall_call+7/11] syscall_call+0x7/0xb

'uname -a':

Linux nika 2.6.0-test4 #1 Mon Aug 25 07:37:38 AKDT 2003 i686 GNU/Linux

'lspci':

00:00.0 Host bridge: VIA Technologies, Inc. VT8366/A/7 [Apollo KT266/A/333]
00:01.0 PCI bridge: VIA Technologies, Inc. VT8366/A/7 [Apollo KT266/A/333 AGP]
00:08.0 SCSI storage controller: LSI Logic / Symbios Logic 53c875 (rev 26)
00:09.0 Ethernet controller: 3Com Corporation 3c905C-TX/TX-M [Tornado] (rev 78)
00:0b.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 08)
00:0b.1 Input device controller: Creative Labs SB Live! MIDI/Game Port (rev 08)
00:11.0 ISA bridge: VIA Technologies, Inc. VT8233 PCI to ISA Bridge
00:11.1 IDE interface: VIA Technologies, Inc. VT82C586/B/686A/B PIPC Bus Master IDE (rev 06)
00:11.2 USB Controller: VIA Technologies, Inc. USB (rev 1b)
00:11.3 USB Controller: VIA Technologies, Inc. USB (rev 1b)
00:11.4 USB Controller: VIA Technologies, Inc. USB (rev 1b)
01:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G400 AGP (rev 85)

'cat /proc/cpuinfo':

processor	: 0
vendor_id	: AuthenticAMD
cpu family	: 6
model		: 6
model name	: AMD Athlon(tm) XP 1800+
stepping	: 2
cpu MHz		: 1540.193
cache size	: 256 KB
fdiv_bug	: no
hlt_bug		: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 1
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 mmx fxsr sse syscall mp mmxext 3dnowext 3dnow
bogomips	: 3039.23

'dmesg':

Linux version 2.6.0-test4 (root@nika) (gcc version 3.2.3 (Debian)) #1 Mon Aug 25 07:37:38 AKDT 2003
Video mode to be used for restore is f00
BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
 BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 000000001fff0000 (usable)
 BIOS-e820: 000000001fff0000 - 000000001fff3000 (ACPI NVS)
 BIOS-e820: 000000001fff3000 - 0000000020000000 (ACPI data)
 BIOS-e820: 00000000ffff0000 - 0000000100000000 (reserved)
511MB LOWMEM available.
On node 0 totalpages: 131056
  DMA zone: 4096 pages, LIFO batch:1
  Normal zone: 126960 pages, LIFO batch:16
  HighMem zone: 0 pages, LIFO batch:1
DMI 2.3 present.
Building zonelist for node : 0
Kernel command line: BOOT_IMAGE=Linux-2.6.0-t4 ro root=301
Local APIC disabled by BIOS -- reenabling.
Found and enabled local APIC!
Initializing CPU#0
PID hash table entries: 2048 (order 11: 16384 bytes)
Detected 1540.193 MHz processor.
Console: colour VGA+ 80x25
Calibrating delay loop... 3039.23 BogoMIPS
Memory: 513896k/524224k available (2788k kernel code, 9580k reserved, 1000k data, 160k init, 0k highmem)
Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
Mount-cache hash table entries: 512 (order: 0, 4096 bytes)
-> /dev
-> /dev/console
-> /root
CPU:     After generic identify, caps: 0383fbff c1cbfbff 00000000 00000000
CPU:     After vendor identify, caps: 0383fbff c1cbfbff 00000000 00000000
CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
CPU: L2 Cache: 256K (64 bytes/line)
CPU:     After all inits, caps: 0383fbff c1cbfbff 00000000 00000020
Intel machine check architecture supported.
Intel machine check reporting enabled on CPU#0.
CPU: AMD Athlon(tm) XP 1800+ stepping 02
Enabling fast FPU save and restore... done.
Enabling unmasked SIMD FPU exception support... done.
Checking 'hlt' instruction... OK.
POSIX conformance testing by UNIFIX
enabled ExtINT on CPU#0
ESR value before enabling vector: 00000000
ESR value after enabling vector: 00000000
Using local APIC timer interrupts.
calibrating APIC timer ...
..... CPU clock speed is 1539.0649 MHz.
..... host bus clock speed is 267.0765 MHz.
PM: Adding info for No Bus:legacy
Initializing RT netlink socket
spurious 8259A interrupt: IRQ7.
PCI: PCI BIOS revision 2.10 entry at 0xfb220, last bus=1
PCI: Using configuration type 1
mtrr: v2.0 (20020519)
BIO: pool of 256 setup, 14Kb (56 bytes/bio)
biovec pool[0]:   1 bvecs: 256 entries (12 bytes)
biovec pool[1]:   4 bvecs: 256 entries (48 bytes)
biovec pool[2]:  16 bvecs: 256 entries (192 bytes)
biovec pool[3]:  64 bvecs: 256 entries (768 bytes)
biovec pool[4]: 128 bvecs: 256 entries (1536 bytes)
biovec pool[5]: 256 bvecs: 256 entries (3072 bytes)
SCSI subsystem initialized
drivers/usb/core/usb.c: registered new driver hub
PCI: Probing PCI hardware
PCI: Probing PCI hardware (bus 00)
PM: Adding info for No Bus:pci0000:00
PM: Adding info for pci:0000:00:00.0
PM: Adding info for pci:0000:00:01.0
PM: Adding info for pci:0000:00:08.0
PM: Adding info for pci:0000:00:09.0
PM: Adding info for pci:0000:00:0b.0
PM: Adding info for pci:0000:00:0b.1
PM: Adding info for pci:0000:00:11.0
PM: Adding info for pci:0000:00:11.1
PM: Adding info for pci:0000:00:11.2
PM: Adding info for pci:0000:00:11.3
PM: Adding info for pci:0000:00:11.4
PM: Adding info for pci:0000:01:00.0
PCI: Using IRQ router default [1106/3099] at 0000:00:00.0
pty: 256 Unix98 ptys configured
Machine check exception polling timer started.
ikconfig 0.5 with /proc/ikconfig
Journalled Block Device driver loaded
Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
NTFS driver 2.1.4 [Flags: R/O].
udf: registering filesystem
Initializing Cryptographic API
Real Time Clock Driver v1.11a
Linux agpgart interface v0.100 (c) Dave Jones
agpgart: Detected VIA Apollo Pro KT266/KT333 chipset
agpgart: Maximum main memory to use for agp memory: 439M
agpgart: AGP aperture is 64M @ 0xe0000000
[drm] Initialized mga 3.1.0 20021029 on minor 0
Hangcheck: starting hangcheck timer 0.5.0 (tick is 180 seconds, margin is 60 seconds).
Using anticipatory scheduling elevator
Floppy drive(s): fd0 is 1.44M
FDC 0 is a post-1991 82077
PM: Adding info for platform:floppy0
loop: loaded (max 8 devices)
3c59x: Donald Becker and others. www.scyld.com/network/vortex.html
0000:00:09.0: 3Com PCI 3c905C Tornado at 0xd400. Vers LK1.1.19
Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
VP_IDE: IDE controller at PCI slot 0000:00:11.1
VP_IDE: chipset revision 6
VP_IDE: not 100% native mode: will probe irqs later
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
VP_IDE: VIA vt8233 (rev 00) IDE UDMA100 controller on pci0000:00:11.1
    ide0: BM-DMA at 0xe000-0xe007, BIOS settings: hda:DMA, hdb:pio
    ide1: BM-DMA at 0xe008-0xe00f, BIOS settings: hdc:DMA, hdd:DMA
hda: Maxtor 4D080H4, ATA DISK drive
PM: Adding info for No Bus:ide0
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
PM: Adding info for ide:0.0
hdc: Maxtor 4G120J6, ATA DISK drive
PM: Adding info for No Bus:ide1
hdd: CR-48X9TE, ATAPI CD/DVD-ROM drive
ide1 at 0x170-0x177,0x376 on irq 15
PM: Adding info for ide:1.0
PM: Adding info for ide:1.1
hda: max request size: 128KiB
hda: 160086528 sectors (81964 MB) w/2048KiB Cache, CHS=65535/16/63, UDMA(100)
 hda: hda1 hda2 hda3 < hda5 hda6 hda7 hda8 hda9 >
hdc: max request size: 1024KiB
hdc: 240121728 sectors (122942 MB) w/2048KiB Cache, CHS=16383/255/63, UDMA(100)
 hdc: hdc1 hdc2 < hdc5 hdc6 hdc7 hdc8 >
hdd: ATAPI 40X CD-ROM CD-R/RW drive, 2048kB Cache, UDMA(33)
Uniform CD-ROM driver Revision: 3.12
sym.0.8.0: setting PCI_COMMAND_INVALIDATE.
sym.0.8.0: 53c875 detected
sym0: <875> rev 0x26 on pci bus 0 device 8 function 0 irq 10
sym0: Tekram NVRAM, ID 7, Fast-20, SE, parity checking
sym0: SCSI BUS has been reset.
scsi0 : sym-2.1.16a
PM: Adding info for No Bus:host0
  Vendor: EXABYTE   Model: EXB-85058HE-0000  Rev: 0108
  Type:   Sequential-Access                  ANSI SCSI revision: 02
PM: Adding info for scsi:0:0:5:0
st: Version 20030811, fixed bufsize 32768, s/g segs 256
Attached scsi tape st0 at scsi0, channel 0, id 5, lun 0
st0: try direct i/o: yes, max page reachable by HBA 1048575
drivers/usb/host/uhci-hcd.c: USB Universal Host Controller Interface driver v2.1
uhci-hcd 0000:00:11.2: UHCI Host Controller
uhci-hcd 0000:00:11.2: irq 11, io base 0000e400
uhci-hcd 0000:00:11.2: new USB bus registered, assigned bus number 1
PM: Adding info for usb:usb1
hub 1-0:0: USB hub found
hub 1-0:0: 2 ports detected
PM: Adding info for usb:1-0:0
uhci-hcd 0000:00:11.3: UHCI Host Controller
uhci-hcd 0000:00:11.3: irq 11, io base 0000e800
uhci-hcd 0000:00:11.3: new USB bus registered, assigned bus number 2
PM: Adding info for usb:usb2
hub 2-0:0: USB hub found
hub 2-0:0: 2 ports detected
PM: Adding info for usb:2-0:0
uhci-hcd 0000:00:11.4: UHCI Host Controller
uhci-hcd 0000:00:11.4: irq 11, io base 0000ec00
uhci-hcd 0000:00:11.4: new USB bus registered, assigned bus number 3
PM: Adding info for usb:usb3
hub 3-0:0: USB hub found
hub 3-0:0: 2 ports detected
PM: Adding info for usb:3-0:0
Initializing USB Mass Storage driver...
drivers/usb/core/usb.c: registered new driver usb-storage
USB Mass Storage support registered.
drivers/usb/core/usb.c: registered new driver hid
drivers/usb/input/hid-core.c: v2.0:USB HID core driver
mice: PS/2 mouse device common for all mice
input: PC Speaker
input: PS2++ Logitech Mouse on isa0060/serio1
serio: i8042 AUX port at 0x60,0x64 irq 12
input: AT Set 2 keyboard on isa0060/serio0
serio: i8042 KBD port at 0x60,0x64 irq 1
PM: Adding info for No Bus:i2c-0
Advanced Linux Sound Architecture Driver Version 0.9.6 (Wed Aug 20 20:27:13 2003 UTC).
ALSA device list:
  #0: Sound Blaster Live! (rev.8) at 0xd800, irq 11
NET4: Linux TCP/IP 1.0 for NET4.0
IP: routing cache hash table of 4096 buckets, 32Kbytes
TCP: Hash tables configured (established 32768 bind 65536)
ip_conntrack version 2.1 (4095 buckets, 32760 max) - 300 bytes per conntrack
ip_tables: (C) 2000-2002 Netfilter core team
ipt_recent v0.3.1: Stephen Frost <sfrost@snowman.net>.  http://snowman.net/projects/ipt_recent/
arp_tables: (C) 2002 David S. Miller
Initializing IPsec netlink socket
NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
kjournald starting.  Commit interval 5 seconds
EXT3-fs: mounted filesystem with ordered data mode.
VFS: Mounted root (ext3 filesystem) readonly.
Freeing unused kernel memory: 160k freed
Adding 1004020k swap on /dev/hda9.  Priority:-1 extents:1
Adding 997880k swap on /dev/hdc8.  Priority:-2 extents:1
EXT3 FS on hda1, internal journal
kjournald starting.  Commit interval 5 seconds
EXT3 FS on hda2, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
kjournald starting.  Commit interval 5 seconds
EXT3 FS on hda5, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
kjournald starting.  Commit interval 5 seconds
EXT3 FS on hda6, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
kjournald starting.  Commit interval 5 seconds
EXT3 FS on hda7, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
kjournald starting.  Commit interval 5 seconds
EXT3 FS on hda8, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
kjournald starting.  Commit interval 5 seconds
EXT3 FS on hdc1, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
kjournald starting.  Commit interval 5 seconds
EXT3 FS on hdc5, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
kjournald starting.  Commit interval 5 seconds
EXT3 FS on hdc6, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
kjournald starting.  Commit interval 5 seconds
EXT3 FS on hdc7, internal journal
EXT3-fs: mounted filesystem with ordered data mode.
nfs warning: mount version older than kernel
nfs warning: mount version older than kernel
nfs warning: mount version older than kernel
nfs warning: mount version older than kernel
nfs warning: mount version older than kernel
nfs warning: mount version older than kernel
nfs warning: mount version older than kernel
process `syslogd' is using obsolete setsockopt SO_BSDCOMPAT
agpgart: Found an AGP 2.0 compliant device at 0000:00:00.0.
agpgart: Putting AGP V2 device at 0000:00:00.0 into 1x mode
agpgart: Putting AGP V2 device at 0000:01:00.0 into 1x mode

Chris
-- 
Christopher S. Swingley          email: cswingle@iarc.uaf.edu
IARC -- Frontier Program         Please use encryption.  GPG key at:
University of Alaska Fairbanks   www.frontier.iarc.uaf.edu/~cswingle/

Re: 2.6.0-test4: Unable to handle kernel NULL pointer dereference

[Andrew Morton]

Christopher Swingley <cswingle@iarc.uaf.edu> wrote:
>
> kernel: Unable to handle kernel NULL pointer dereference at virtual address 00000000
> ...
> kernel: EIP is at find_inode_fast+0x1a/0x60
> ...
> model name	: AMD Athlon(tm) XP 1800+
> ...

You've been bitten by the athlon-prefetch(0)-goes-oops problem.

Nobody seems to be working this, so I'll be sending the below in to Linus.

--- 25/include/asm-i386/processor.h~disable-athlon-prefetch	2003-08-23 13:48:16.000000000 -0700
+++ 25-akpm/include/asm-i386/processor.h	2003-08-23 13:48:16.000000000 -0700
@@ -578,6 +578,8 @@ static inline void rep_nop(void)
 #define ARCH_HAS_PREFETCH
 extern inline void prefetch(const void *x)
 {
+	if (cpu_data[0].x86_vendor == X86_VENDOR_AMD)
+		return;
 	alternative_input(ASM_NOP4,
 			  "prefetchnta (%1)",
 			  X86_FEATURE_XMM,

_

Re: 2.6.0-test4: Unable to handle kernel NULL pointer dereference

[Bill Davidsen]

On Thu, 28 Aug 2003, Andrew Morton wrote:

> Christopher Swingley <cswingle@iarc.uaf.edu> wrote:
> >
> > kernel: Unable to handle kernel NULL pointer dereference at virtual address 00000000
> > ...
> > kernel: EIP is at find_inode_fast+0x1a/0x60
> > ...
> > model name	: AMD Athlon(tm) XP 1800+
> > ...
> 
> You've been bitten by the athlon-prefetch(0)-goes-oops problem.
> 
> Nobody seems to be working this, so I'll be sending the below in to Linus.

Let's not. If this goes in the Athlon users will get bad performance,
reliable operation, and no one will blame anything but the Athlon... If
it keeps oopsing hopefully people will complain and it will get fixed.

Taking out features instead of fixing them is a bad president, this is
not a driver for an obsolete ISA card, this is a performance boost for a
very current CPU. I'm surprised AMD hasn't looked at it themselves.

> 
> --- 25/include/asm-i386/processor.h~disable-athlon-prefetch	2003-08-23 13:48:16.000000000 -0700
> +++ 25-akpm/include/asm-i386/processor.h	2003-08-23 13:48:16.000000000 -0700
> @@ -578,6 +578,8 @@ static inline void rep_nop(void)
>  #define ARCH_HAS_PREFETCH
>  extern inline void prefetch(const void *x)
>  {
> +	if (cpu_data[0].x86_vendor == X86_VENDOR_AMD)
> +		return;
>  	alternative_input(ASM_NOP4,
>  			  "prefetchnta (%1)",
>  			  X86_FEATURE_XMM,
> 
> _
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 

-- 
bill davidsen <davidsen@tmr.com>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.

Re: 2.6.0-test4: Unable to handle kernel NULL pointer dereference

[Andrew Morton]

Bill Davidsen <davidsen@tmr.com> wrote:
>
> Let's not. If this goes in the Athlon users will get bad performance,
>  reliable operation, and no one will blame anything but the Athlon... If
>  it keeps oopsing hopefully people will complain and it will get fixed.

Tough luck.  It is not acceptable to have -test kernels oopsing all over
the place.

If anyone cares about the performance then they'll fix it for real.  It's
probably unmeasurable anyway.

Re: 2.6.0-test4: Unable to handle kernel NULL pointer dereference

[Randy.Dunlap]

> On Thu, 28 Aug 2003, Andrew Morton wrote:
>
>> Christopher Swingley <cswingle@iarc.uaf.edu> wrote:
>> >
>> > kernel: Unable to handle kernel NULL pointer dereference at virtual
>> address 00000000 ...
>> > kernel: EIP is at find_inode_fast+0x1a/0x60
>> > ...
>> > model name	: AMD Athlon(tm) XP 1800+
>> > ...
>>
>> You've been bitten by the athlon-prefetch(0)-goes-oops problem.
>>
>> Nobody seems to be working this, so I'll be sending the below in to Linus.
>
> Let's not. If this goes in the Athlon users will get bad performance,
> reliable operation, and no one will blame anything but the Athlon... If it
> keeps oopsing hopefully people will complain and it will get fixed.
>
> Taking out features instead of fixing them is a bad president, this is not a
> driver for an obsolete ISA card, this is a performance boost for a very
> current CPU. I'm surprised AMD hasn't looked at it themselves.

Is this the same issue as
  http://marc.theaimsgroup.com/?l=linux-kernel&m=106080170017645&w=2
in which AMD said, "Let us get back to you, ok?" on Aug. 13?

~Randy

Re: 2.6.0-test4: Unable to handle kernel NULL pointer dereference

[Andrew Morton]

"Randy.Dunlap" <rddunlap@osdl.org> wrote:
>
> Is this the same issue as
>    http://marc.theaimsgroup.com/?l=linux-kernel&m=106080170017645&w=2
>  in which AMD said, "Let us get back to you, ok?" on Aug. 13?

yes.

Re: 2.6.0-test4: Unable to handle kernel NULL pointer dereference

[Alan Cox]

On Gwe, 2003-08-29 at 03:40, Andrew Morton wrote:
> "Randy.Dunlap" <rddunlap@osdl.org> wrote:
> >
> > Is this the same issue as
> >    http://marc.theaimsgroup.com/?l=linux-kernel&m=106080170017645&w=2
> >  in which AMD said, "Let us get back to you, ok?" on Aug. 13?
> 
> yes.

The extra if also seems to ruin PIV performance, but I still agree with
Andrew - you can test code easily with known oopses. Things like the
known local root holes in 2.6test aren't a problem but random oopses 
mean you can't tell a new bug from the old one.

Re: 2.6.0-test4: Unable to handle kernel NULL pointer dereference

[Hollis Blanchard]

On Thursday, Aug 28, 2003, at 15:10 US/Central, Andrew Morton wrote:
>
> --- 25/include/asm-i386/processor.h~disable-athlon-prefetch	2003-08-23 
> 13:48:16.000000000 -0700
> +++ 25-akpm/include/asm-i386/processor.h	2003-08-23 13:48:16.000000000 
> -0700
> @@ -578,6 +578,8 @@ static inline void rep_nop(void)
>  #define ARCH_HAS_PREFETCH
>  extern inline void prefetch(const void *x)
>  {
> +	if (cpu_data[0].x86_vendor == X86_VENDOR_AMD)
> +		return;
>  	alternative_input(ASM_NOP4,
>  			  "prefetchnta (%1)",
>  			  X86_FEATURE_XMM,

Without a comment explaining the problem?

-- 
Hollis Blanchard
IBM Linux Technology Center