Bug#682233: mpt2sas: kernel crash under load with hanged disks

[Jonathan Nieder <jrnieder@gmail.com>]

George Shuklin wrote:

> I think that problem is specific to LSI drivers, not to linux-raid,
> because same tests with Adaptec (aacraid) and few onboard HBAs show
> no signs of crashing (hanged disks is just marked as 'failed' and
> all systems behave as expected).

Thanks.  Very useful.

[...]
> linux-3.0 do have mpt2sas 08.100.00.02  and linux-3.2 do have 10.100.00.00

Between 3.0 and 3.2.12, the mpt2sas driver had 30 patches.  That would
be an interesting test: could you try a current kernel with the
mpt2sas driver from 3.0.y?  It works like this:

 0. prerequisites:

	apt-get install git build-essential

 1. get the kernel history, if you don't already have it:

	git clone \
	  git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

 2. fetch point releases:

	cd linux
	git remote add stable \
	  git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
	git fetch stable

 3. configure, build, test:

	git checkout origin/master
	cp /boot/config-$(uname -r) .config; # current configuration
	scripts/config --disable DEBUG_INFO
	make localmodconfig; # optional: minimize configuration
	make deb-pkg; # optionally with -j<num> for parallel build
	dpkg -i ../<name of package>; # as root
	reboot
	... test test test ...

    Hopefully it reproduces the bug.  So

 4. try the mpt2sas driver from 3.0.y:

	cd linux
	git checkout stable/linux-3.0.y -- drivers/scsi/mpt2sas
	make deb-pkg; # maybe with -j4
	dpkg -i ../<name of package>
	reboot
	... test ...

Jonathan