Created attachment 918010 [details]
kernel lockup 1
Description of problem:
When booting to an iSCSI target on kernel 3.15.3 and 3.15.4 it appears that a recent commit is causing a NULL pointer dereference
Version-Release number of selected component (if applicable):
Booting multi-user or single-user to an iSCSI target
Kernel locks up with the following messages, to name a few:
[ 19.672549] BUG: unable to handle kernel NULL pointer dereference at 000000000000000c [ 19.680405] IP:  iscsi_tcp_segment_done+0x2a8/0x370 [libiscsi_tcp]
System boots multi/single-user successfully
Looks to be the problem commit as referenced in this message: http://www.spinics.net/linux/lists/kernel/msg1776379.html
The fix may have already been commited to -stable upstream here: https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/?id=refs%2Ftags%2Fv3.15.5&qt=grep&q=iscsi
but does not appear to be in the fedora kernel yet
Apologies for the attached pictures, it's been difficult to gather boot messages with our setup, but if more information is needed we can definitely provide it!
Created attachment 918012 [details]
kernel lockup 2
Could you please try the 3.15.5 kernel build? It contains this commit:
Author: Martin K. Petersen <firstname.lastname@example.org>
Date: Tue Jun 24 16:59:35 2014 +0200
SCSI: use the scsi data buffer length to extract transfer size
commit 5616b0a46ed82eb9a093f752fc4d7bd3cc688583 upstream.
which is the commit you pointed to in the mailing list threads.
Just tested 3.15.5-200.fc20.x86_64 and this resolves the error, thanks!
kernel-3.15.5-200.fc20 has been submitted as an update for Fedora 20.
kernel-3.15.5-200.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.