Subject: kern/37093: itimer problems
To: None <email@example.com, firstname.lastname@example.org,>
From: None <email@example.com>
Date: 10/09/2007 13:05:01
>Synopsis: itimer problems
>Arrival-Date: Tue Oct 09 13:05:01 +0000 2007
>Originator: Andrew Doran
>Release: NetBSD 4.99.32
The NetBSD Project
itimers are fired from hardclock(). There are a few problems:
- itimer code run in process context has scant splsched() protection
- hardclock() is called w/o kernel_lock held and the code is not MP
- itimerfire() may try to send signals with ksiginfo, which will
use ksiginfo_pool and thus the VM system above IPL_VM.
- Defer sending signals to a soft interrupt.
- Spinlock the itimers.