Subject: Re: CVS commit: src/sys/net80211
To: None <>
From: Steve Woodford <>
List: source-changes
Date: 11/21/2005 12:58:06
On Sunday 20 November 2005 10:16, David Young wrote:

> Set the "special" struct ieee80211_channel pointer,
> IEEE80211_CHAN_ANYC, to 0x1 instead of 0xffff, so the kernel will trap
> accidental
> dereferences.  I don't set IEEE80211_CHAN_ANYC to NULL because it
> may have a distinct meaning in net80211.  Thanks to Steve Woodford
> for pointing out that 0xffff may be a valid kernel memory address
> on x86.

It's not a particularly serious issue, it's more the case that it *might* 
be a valid userland address from the kernel's PoV, though misaligned, on 
some platforms.

x86 is one platform where misaligned accesses are permitted. Though I 
don't think 0xffff has been a valid userland address on x86 since the 
days of a.out. On some PowerPC platforms, 0xffff is within the kernel's 
own address space...

Cheers, Steve