I am forwarding this e-mail to let you know about a bugzilla that was filled involving the dm-crypt driver and cciss. From my testing and the debug I have put into the kernel it seems that when the dm-crypt driver is sitting on top of the cciss driver it is not adhering to our scatter gather element limitation of 31. I see that the bio that is created and turned into a request by the dm-crypt driver can contain 64 sg elements which causes us to throw a bug in our request routine. I noticed that the comments in crypt_alloc_buffer say not to violate the device limitations but I did not see any code that actually checks those limitations. In other dm modules I noticed code such a __split_bio which seemed to be breaking up bio's based on the limitations of the lower level. Could you please have someone join this bugzilla and look into this issue? I have attached the debug output from the serial console on my system to the issue. Please let me know what I can do to help. Thank You, Chase Maupin HP Linux Storage Drivers Houston, TX -----Original Message----- From: bugme-daemon@xxxxxxxxxxxxxxxxxxx [mailto:bugme-daemon@xxxxxxxxxxxxxxxxxxx] Sent: Friday, January 05, 2007 10:42 AM To: Maupin, Chase Subject: [Bug 7763] kernel panic on writing to dm-crypt->cciss partition http://bugzilla.kernel.org/show_bug.cgi?id=7763 ------- Additional Comments From chase.maupin@xxxxxx 2007-01-05 08:35 ------- Hermann, I have found that the dm-crypt module is violating our queue limitations for the number of scatter gather elements we can handle per request. I have captured this in the debug output I have attached to this issue. I am going to work with the RedHat dm development to get this resolved as this issue does not seem to be present in other dm modules. I have seen some code in these other modules such as __split_bio which seems to break up the data based on the low level device limitations as reported by the driver. The crypt function crypt_alloc_buffer says in the comments that it should not violate these limits, but I did not find code to verify that this is true. I found that in the crypt_alloc_buffer function we are seeing bio structures with more than 31 segments which later get sent to the cciss driver as requests. I will send this bugzilla to the RedHat dm mailing list so that they can keep it up to date. Thanks for your help on this. Chase ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
