atimes of binaries not properly updated

[Dionysus Blazakis]

On Wed, May 21, 2008 at 4:03 PM, Dionysus Blazakis
<dion.blazakis at gmail.com> wrote:
> On Tue, May 20, 2008 at 3:53 PM, Dionysus Blazakis
> <dion.blazakis at gmail.com> wrote:
>> On Mon, May 19, 2008 at 2:26 PM, Simon 'corecode' Schubert
>> <corecode at fs.ei.tum.de> wrote:
>>> Hey,
>>>
>>> something is wrong with our atimes update:
>>>
>>> % stat -x `which mplayer`
>>>  File: "/usr/pkg/bin/mplayer"
>>>  Size: 21084730     FileType: Regular File
>>>  Mode: (0555/-r-xr-xr-x)         Uid: (    0/    root)  Gid: (    0/ wheel)
>>> Device: 91,3   Inode: 579162    Links: 1
>>> Access: Fri May  2 01:00:44 2008
>>> Modify: Wed Apr 30 00:16:03 2008
>>> Change: Wed Apr 30 00:16:03 2008
>>>
>>> But I'm sure I watched MacGyver yesterday night, with mplayer.  Maybe it was
>>> in the buffer cache since May 2nd and thus was not updated?  Actually
>>> running mplayer right now (after reboot) does not update the atime either.
>>
>> I took a look and it seems like bumping atime on a execve or mmap was
>> never done.  The other BSDs and Linux _do_.  I took a shot at a patch.
>>  It is based on FBSD.
>>
>> The patch against HEAD is at:
>> http://dblaz.beevomit.org/dfly/atime.patch
>
> Based on some discussion in IRC, I added a check in case vn_mark_atime
> was called without a process context.  For now, it will use NOCRED in
> this case (equivalent to NULL).
>
> I also added the note to the man page.
>
> Updated patch:
> http://dblaz.beevomit.org/dfly/atime-2.patch
>
> -- Dion
>
>>
>> I wasn't sure if the atime update in mmap should happen further below
>> or not.  Also, not sure if I had to mess with vnode locking in
>> kern_exec -- please let me know.
>>
>> -- Dion
>>
>> Ah, and I just thought that maybe our stat(2) man page should be
>> updated to add execve and mmap in the atime blurb.
>>
>>>
>>> cheers
>>>  simon
>>>
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>>>
>>
>

Hrm.  Nevermind.  The ucred's passed to the fs vnops are dereferenced
without check.