* Christoph Hellwig [off-list ref] wrote:

On Fri, Jul 01, 2011 at 04:37:35PM +0200, Ingo Molnar wrote:

quoted

After initial modules have loaded i essentially disable crash.ko 
via /proc/sys/kernel/modules_disabled so rootkits have to work a 
bit harder than that.

Not sure for fedora as I don'[t have a kernel tree at hand right 
now, but for x86 systems at least RHEL6 has the module built in. 
[...]

Fedora Rawhide has it modular:

 # grep CRASH /boot/config-2.6.38-0.rc7.git2.3.fc16.x86_64
 CONFIG_CRASH=m

 # rpm -ql kernel-2.6.38-0.rc7.git2.3.fc16.x86_64 | grep crash
 /lib/modules/2.6.38-0.rc7.git2.3.fc16.x86_64/kernel/drivers/char/crash.ko

[...]  Either way we'll need some way to support crash properly in 
mainline, preferably in a boot-time opt-in way. [...]

Yes, boot-time opt-in was what i suggested.

[...] I'd tend slightly toward optionally enabling /dev/mem for it 
instead of a separate driver, but if people prefer a different 
route I'm fine, too.

No, sharing the driver is perfectly fine and sane as long as this 
weird usage is not enabled widely.

Note that for normal crash usage read only access is just fine.

That's true as well. Petr?

Thanks,

	Ingo