[BUG] jiffies counter leaps in 2.6.24-rc3

Stefano Brivio
2007-11-24T17:26:40Z

It looks like the jiffies counter sometimes jumps back and forth of some
hundreds seconds in 2.6.24-rc3. I observed that this happens when I use the
su(1) command, e.g.:

Nov 24 06:17:17 morte [190769.065301] wmaster0: STA 00:14:c1:35:8d:eb Average rate: 232 (6730/29)
Nov 24 06:17:22 morte su[16826]: Successful su for root by st3
Nov 24 06:17:22 morte su[16826]: + pts/1 st3:root
Nov 24 06:17:22 morte su(pam_unix)[16826]: session opened for user root by (uid=1000)
Nov 24 06:17:38 morte [715682.606983] b43-phy2 ERROR: PHY transmission error
Nov 24 06:18:17 morte [715707.765415] wmaster0: STA 00:14:c1:35:8d:eb Average rate: 194 (970/5)

or

Nov 23 20:55:40 morte [627074.320296] wmaster0: STA 00:14:c1:35:8d:eb Average rate: 10 (550/55)
Nov 23 20:56:01 morte su[5452]: Successful su for root by st3
Nov 23 20:56:01 morte su[5452]: + pts/4 st3:root
Nov 23 20:56:01 morte su(pam_unix)[5452]: session opened for user root by (uid=1000)
Nov 23 20:56:03 morte su(pam_unix)[5452]: session closed for user root
Nov 23 20:56:40 morte [167187.102931] wmaster0: STA 00:14:c1:35:8d:eb Average rate: 10 (40/4)

or

Nov 23 06:31:00 morte [156536.124549] wmaster0: STA 00:14:c1:35:8d:eb Average rate: 240 (6480/27)
Nov 23 06:31:58 morte su[4350]: Successful su for root by st3
Nov 23 06:31:58 morte su[4350]: + pts/0 st3:root
Nov 23 06:31:58 morte su(pam_unix)[4350]: session opened for user root by (uid=1000)
Nov 23 06:32:09 morte [587438.574530] wmaster0: STA 00:14:c1:35:8d:eb Average rate: 240 (4080/17)

(I checked with a clock the timestamp prepended by syslog-ng, and it's
correct.)

I'm thinking this could be somehow related to the setpriority() call made
by su(1), but I don't know how to debug this further. Any clue?

morte st3 # cat /proc/interrupts
CPU0
0: 319167512 XT-PIC-XT timer
1: 459332 XT-PIC-XT i8042
2: 0 XT-PIC-XT cascade
3: 1 XT-PIC-XT
4: 1 XT-PIC-XT
5: 1 XT-PIC-XT
7: 9 XT-PIC-XT
8: 2 XT-PIC-XT rtc
9: 9114 XT-PIC-XT acpi
10: 46272099 XT-PIC-XT uhci_hcd:usb1, i915@pci:0000:00:02.0
11: 23691749 XT-PIC-XT yenta, Intel 82801DB-ICH4, uhci_hcd:usb2, uhci_hcd:usb3, ehci_hcd:usb4, Intel 82801DB-ICH4 Modem, ohci1394, b43
12: 3287633 XT-PIC-XT i8042
14: 1076167 XT-PIC-XT ide0
15: 47 XT-PIC-XT ide1
NMI: 0 Non-maskable interrupts
LOC: 0 Local timer interrupts
TRM: 0 Thermal event interrupts
SPU: 0 Spurious interrupts
ERR: 8
MIS: 0

morte st3 # cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 13
model name : Intel(R) Pentium(R) M processor 1.50GHz
stepping : 6
cpu MHz : 1500.000
cache size : 2048 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr mce cx8 sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe bts est tm2
bogomips : 2993.47
clflush size : 64

--
Ciao
Stefano