alarm() does not work/ping only sends one packet on SMP machine (2.2.16)

Tobias Haustein (tobias.haustein@aixigo.de)
Tue, 17 Jul 2001 14:02:07 +0200


Hi!

I've got a problem on a production database server (SuSE Linux 7.0,
Kernel 2.2.16 SMP). On this machine, a ping to any network (also ping
localhost) does only send one packet. However, a ping -l 10 sends
exactly 11 packets. Thus, the problem seems not to be the network, but
another part of the system. I've tracked the problem down to the alarm()
function. The following program runs forever:

---
#include <unistd.h>

int main() { alarm( 1 );

while( 1 ); }

---

On any other machine, the program receives an SIGALRM, but on this particular machine, nothing happens.

Question: What might be the cause for this?

Then, I think that the following is strange: There are two uptime counters accessible through /proc/uptime. These counters show a difference of about 28 hours! The difference is still growing, as the following skript shows:

--
#!/bin/bash
while true; do =

sleep 2 echo -n `date` cat /proc/uptime | awk '{FS=3D" ";printf " - %02d:%02d:%02d\n", int(($1-$2)/3600), int(($1-$2)/60)%60, int(($1-$2)%60);}' done

--

Output: =

Fri Jun 22 21:49:53 CEST 2001 - 28:30:40 Fri Jun 22 21:49:55 CEST 2001 - 28:30:40 Fri Jun 22 21:49:57 CEST 2001 - 28:30:41 Fri Jun 22 21:49:59 CEST 2001 - 28:30:41

Question: Is this normal?

Hardware: 2 x Pentium III, ServerWorks chipset on Intel board, 512 MB RAM, GDT Vortex RAID, 3c905C-TX

-------------------------------------------------- =

Some info from /proc follows: -------------------------------------------------- root # cat /proc/interrupts =

CPU0 CPU1 =

0: 1211049447 0 XT-PIC timer 1: 8 8 IO-APIC-edge keyboard 2: 0 0 XT-PIC cascade 8: 1 1 IO-APIC-edge rtc 12: 0 0 IO-APIC-edge PS/2 Mouse 13: 1 0 XT-PIC fpu 15: 7708 8516 IO-APIC-edge ide1 18: 25888364 26299521 IO-APIC-level gdth 20: 37673025 39437027 IO-APIC-level eth0 22: 20 20 IO-APIC-level HiSax 31: 3755190 4144920 IO-APIC-level eth1 NMI: 0 ERR: 0

root # # cat /proc/cpuinfo =

processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 8 model name : Pentium III (Coppermine) stepping : 6 cpu MHz : 799.643 cache size : 256 KB fdiv_bug : no hlt_bug : no sep_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 pae mce cx8 apic sep mtrr pge mca cmov pat pse36 mmx fxsr xmm bogomips : 1595.80

processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 8 model name : Pentium III (Coppermine) stepping : 6 cpu MHz : 799.643 cache size : 256 KB fdiv_bug : no hlt_bug : no sep_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 pae mce cx8 apic sep mtrr pge mca cmov pat pse36 mmx fxsr xmm bogomips : 1599.08

root # cat /proc/pci PCI devices found: Bus 0, device 0, function 1: Host bridge: Unknown vendor CNB30LE PCI Bridge (rev 5). Medium devsel. Master Capable. Latency=3D16. =

Bus 0, device 0, function 0: Host bridge: Unknown vendor CNB30LE PCI Bridge (rev 5). Medium devsel. Master Capable. Latency=3D32. =

Bus 0, device 1, function 0: VGA compatible controller: ATI Unknown device (rev 122). Vendor id=3D1002. Device id=3D4756. Medium devsel. Fast back-to-back capable. IRQ 16. Master Capable. Latency=3D64. Min Gnt=3D8. Prefetchable 32 bit memory at 0xfd000000 [0xfd000008]. I/O at 0xd800 [0xd801]. Non-prefetchable 32 bit memory at 0xfeaff000 [0xfeaff000]. Bus 0, device 2, function 0: SCSI storage controller: VORTEX Unknown device (rev 0). Vendor id=3D1119. Device id=3D139. Medium devsel. Fast back-to-back capable. IRQ 18. Master Capable. Latency=3D64. =

Prefetchable 32 bit memory at 0xfe6fc000 [0xfe6fc008]. Bus 0, device 3, function 0: Ethernet controller: 3Com Unknown device (rev 116). Vendor id=3D10b7. Device id=3D9200. Medium devsel. IRQ 20. Master Capable. Latency=3D64. Min Gnt=3D10.Max Lat=3D10. I/O at 0xdc00 [0xdc01]. Non-prefetchable 32 bit memory at 0xfeafef00 [0xfeafef00]. Bus 0, device 4, function 0: Network controller: AVM A1 (Fritz) (rev 2). Medium devsel. Fast back-to-back capable. IRQ 22. =

Non-prefetchable 32 bit memory at 0xfeafefe0 [0xfeafefe0]. I/O at 0xdf80 [0xdf81]. Bus 0, device 6, function 0: Ethernet controller: Intel 82557 (rev 8). Medium devsel. Fast back-to-back capable. IRQ 31. Master Capable. Latency=3D64. Min Gnt=3D8.Max Lat=3D56. Non-prefetchable 32 bit memory at 0xfeaee000 [0xfeaee000]. I/O at 0xd400 [0xd401]. Non-prefetchable 32 bit memory at 0xfe900000 [0xfe900000]. Bus 0, device 15, function 0: ISA bridge: Unknown vendor Unknown device (rev 79). Vendor id=3D1166. Device id=3D200. Medium devsel. Master Capable. No bursts. =

Bus 0, device 15, function 1: IDE interface: Unknown vendor Unknown device (rev 0). Vendor id=3D1166. Device id=3D211. Medium devsel. Master Capable. Latency=3D64. =

I/O at 0xffa0 [0xffa1]. Bus 0, device 15, function 2: USB Controller: Unknown vendor Unknown device (rev 4). Vendor id=3D1166. Device id=3D220. Medium devsel. Fast back-to-back capable. IRQ 10. Master Capable. Latency=3D64. Max Lat=3D80. Non-prefetchable 32 bit memory at 0xfeaef000 [0xfeaef000]. Bus 1, device 3, function 0: SCSI storage controller: Adaptec AIC-7892 (rev 2). Medium devsel. Fast back-to-back capable. BIST capable. IRQ 28. Master Capable. Latency=3D64. Min Gnt=3D40.Max Lat=3D25. I/O at 0xe800 [0xe801]. Non-prefetchable 64 bit memory at 0xfebff000 [0xfebff004].

--

Ciao,

Tobias

--
Dipl. Inform. Tobias Haustein

aixigo AG - financial training, research and technology Schloß-Rahe-Straße 15, 52072 Aachen, Germany fon: +49 (0)241 936737-40, fax: +49 (0)241 936737-99 eMail: tobias.haustein@aixigo.de, web: http://www.aixigo.de - 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/