select, jiffies, and SIGALRM

[Vx Glenn]

Hi all,

I am seeing an issue relating to the jiffies counter wrapping around
at 0x7FFFFFFF.

This is a legacy application, and when it runs on 32-bit Unix-Like
OS's, the application silently dies without leaving core after 248
days.

I was able to manipulate the jiffies counter and run the application.
I was able to reproduce the problem. I captured an strace log, and I
see that SIGALRM (alarm clock) is raised after select times out
(because of no data).

I can add a signal handler to intercept the SIGALRM. But my question
is, why should the signal be raised?

---[ strace.log ]---
select(1024, [3 4 5 6], NULL, NULL, {0, 320000}) = 0 (Timeout)
getitimer(ITIMER_REAL, {it_interval={2147157, 520}, it_value={0, 684895}}) = 0
adjtimex({modes=32769, offset=0, freq=0, maxerror=16384000,
esterror=16384000, status=64, constant=2, precision=1,
tolerance=33554432, time={1097551596, 43475}}) = 5
getitimer(ITIMER_REAL, {it_interval={2147157, 520}, it_value={0, 684895}}) = 0
select(1024, [3 4 5 6], NULL, NULL, {1, 0}) = ? ERESTARTNOHAND (To be restarted)
--- SIGALRM (Alarm clock) @ 0 (0) ---
Process 4881 detached
---[ eof strace.log ]---


Anyone have any ideas?


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