Date: Wed, 22 Sep 2010 12:11:10 -0700 From: "Ricky Charlet" <RCharlet@adaranet.com> To: "freebsd-drivers@freebsd.org" <freebsd-drivers@freebsd.org> Subject: newbie trouble with destroy_dev Message-ID: <32AB5C9615CC494997D9ABB1DB12783C024C95033B@SJ-EXCH-1.adaranet.com>
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Howdy,
My goal is to destroy a character device which is currently open for read. Is that allowable? I'm hoping the userland program doing the reading will simply get a read error back (possibly with no data or truncated data).
My experience so far is that I crash the box.
I'm using BSD 8.0. My program with the driver is a kernel module. Upon using the `kldunload` utility, the d_close() method is called. I have tried these logic flows:
Test 1
---------------------
Unhook my packet-filter-hooks
cv_broadcast;
cv_destory
mMtx_destroy
destroy_dev
free associated buffers
Test 2
--------------------
Unhook my packet-filter-hooks
cv_broadcast;
cv_destory
mMtx_destroy
destroy_dev_sched_cb
free associated buffers
Test 3
----------------------
Unhook my packet-filter-hooks
cv_broadcast;
cv_destory
mMtx_destroy
free associated buffers
In all cases I get a kernel crash and the system reboots. Note that the userland program has the associated charater device open and is in a for-ever loop reading the fd.
I'm a newbie and have not yet attached a debugger. I'll go start reading about that and trying it out while I hopefully await replies.
---
Ricky Charlet
Adara Networks<http://www.adaranet.com/welcome.html>;
USA 408-433-4942
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