[SunHELP] Solaris 2.6 : some syscalls Hanging

[DAUBIGNE Sebastien - BOR ( <SDaubigne at bordeaux-bersol.sema.slb.com> <SDaubigne at bordeaux-bersol.sema.slb.com>]

Solaris 2.6, kernel 105181-28.

We'got some processes "hanging" (i.e. with blocking syscalls):

vmstat, iostat, mpstat are hanging on poll() syscall : they open
"/dev/kstat", issue some ioctl() on.it, and wait for data with poll(). But,
poll() never returns.
sar is working fine (note that it doesn't use poll()).
We also have some Oracle background and shadow processes hanging on semop()

Other processes are working fine (those that don't call poll() or semop()).

It seems some kernel syscall (at least poll() and semop()) are waiting
indefinitely :  Looks like some deadlock.
System activity is low (sar shows 70% CPU free, lots of memory free, no page
scan). The only thing I can't see is mutex contention, as mpstat is hanging.

Any idea ?

---
Sebastien DAUBIGNE 
sdaubigne at bordeaux-bersol.sema.slb.com
<mailto:sdaubigne at bordeaux-bersol.sema.slb.com>  - (+33)5.57.26.56.36
SchlumbergerSema - SGS/DWH/Pessac