Re: 2.4.1-pre7 raid5syncd oops

>>>>> "NB" == Neil Brown <[e-mail]> writes:

NB> On  January 16, [e-mail] wrote:

NB> Or in short "this cannot happen" :-)

NB> Is there any chance of a memory error?

NB> Has this happened more than once?

I have to confess that I was not running with the stock
2.4.1-pre7 drivers/md/raid5.c; instead I compiled it with the
change in -ac9 tree, which checks the return value of
alloc_page() early (around line 160).  Also I had your ``Desk
check'' patch (responding to [e-mail]'s post) from
linux-raid list (around line 1075), and mingo's
hot-add/hot-remove fixes.

The symptom was very reproducible with that particular kernel
(essentially, early in the every reboot sequence I got the same
error).  In the end, I had to futz with partition type to
disable autodetection of those offending raid-5 component
partitions to recover from the failure.  Since then I reverted
back to the stock 2.4.1-pre7 driver with only the ``Desk check''
and mingo's hot-add/hot-remove patch, and have not seen the
problem again.  It appears that using those early-null-check
code from -ac9 without understanding its implications was purely
my stupidity, but I still do not offhand see why that would
hurt...