Bug 599464

Summary:	sys-kernel/gentoo-sources - megaraid_sas driver broken
Product:	Gentoo Linux	Reporter:	Thomas Deutschmann (RETIRED) <whissi>
Component:	Current packages	Assignee:	Gentoo Kernel Bug Wranglers and Kernel Maintainers <kernel>
Status:	RESOLVED FIXED
Severity:	normal	CC:	hydrapolic
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
URL:	http://marc.info/?l=linux-scsi&m=147868920429684&w=2
Whiteboard:
Package list:		Runtime testing required:	---

Description Thomas Deutschmann (RETIRED) gentoo-dev

2016-11-11 13:15:57 UTC

Warning: There's an upcoming patch which will be part of any stable kernel (already released in linux-4.4.31) which will break most devices using the megaraid_sas drivers. The bad commit is:

> scsi: megaraid_sas: Fix data integrity failure for JBOD (passthrough) devices
> 
> Commit 02b01e010afe ("megaraid_sas: return sync cache call with
> success") modified the driver to successfully complete SYNCHRONIZE_CACHE
> commands without passing them to the controller. Disk drive caches are
> only explicitly managed by controller firmware when operating in RAID
> mode. So this commit effectively disabled writeback cache flushing for
> any drives used in JBOD mode, leading to data integrity failures.
> 
> [mkp: clarified patch description]
> 
> Fixes: 02b01e010afeeb49328d35650d70721d2ca3fd59

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=1e793f6fc0db920400574211c48f9157a37e3945

Once you boot a kernel containing this patch you RAID adapter won't see any disks/volumes anymore.

Downgrading the kernel solves the problem. Or you can apply the patch from $URL to solve the problem.

Comment 1 Alice Ferrazzi Gentoo Infrastructure

2016-11-15 11:35:14 UTC

fixed by:
4.4.32
https://github.com/gentoo/gentoo/commit/afd410a0fb662d731d96357ed4a5c527698bb189
4.8.8
https://github.com/gentoo/gentoo/commit/ab2d607a638557dc0e462b12a0ed8e003b9cd4b5

Comment 2 Alice Ferrazzi Gentoo Infrastructure

2016-11-18 17:18:23 UTC

can you confirm is fixed in that version ?

Comment 3 Thomas Deutschmann (RETIRED) gentoo-dev

2016-11-18 18:22:53 UTC

Well, only the 4.4.x LTS branch was affected.

The bad commit didn't appear in any other branches.


4.4.x was fixed with =sys-kernel/gentoo-sources-4.4.32 which contains ae94da4c53b77058241fd3551f55cd40327be37d.

4.8.x which was never affected carries both commits (the bad one, 32f60e9b621fff93433fe398cedde009f184c63e and the fix, 8ed841d6c045c31c3309b70395b920cb707537d4) in 4.8.7.


So if we make sure that =sys-kernel/gentoo-sources-4.4.31 never goes stable (probably apply a pmask) we can close this bug as resolved.

Comment 4 Mike Pagano gentoo-dev

2016-11-26 17:30:39 UTC

I just removed the affected version so I'm closing this one.