Re: CVS commit: src/sys/kern

[yamt%mwd.biglobe.ne.jp@localhost (YAMAMOTO Takashi)]

hi,

> On Sat, May 16, 2009 at 12:02:00PM +0000, YAMAMOTO Takashi wrote:
>> Module Name: src
>> Committed By:        yamt
>> Date:                Sat May 16 12:02:00 UTC 2009
>> 
>> Modified Files:
>>      src/sys/kern: init_sysctl.c
>> 
>> Log Message:
>> sysctl_doeproc:
>>      - simplify.
>>      - KERN_PROC: fix possible stale proc pointer dereference.
>>      - KERN_PROC: don't do copyout with proc_lock held.
> 
> IIRC this used to work because it locked the userspace buffer into
> physical memory earlier.

vslock stuff has always been broken.

> I've not looked at the change,

i guess you should look at the change.

> but if you release proc_lock it is
> very difficult to ensure you see every process [1], and that the
> count of processes is correct.
> 
> [1] consider what happens if the proc table has to be extended,
> or when a process is in a fork/exit loop.

right.
is it a problem?

YAMAMOTO Takashi

> 
>       David
> 
> -- 
> David Laight: david%l8s.co.uk@localhost