On Wed, Jan 24, 2018 at 09:30:33AM -0800, Nathan March wrote:
-----Original Message----- From: CentOS-virt [mailto:centos-virt-bounces@centos.org] On Behalf Of Johnny Hughes Sent: Wednesday, January 24, 2018 6:39 AM To: centos-virt@centos.org Subject: Re: [CentOS-virt] Xen 4.6.6-9 (with XPTI meltdown mitigation) packages making their way to centos-virt-xen-testing
On 01/24/2018 01:01 AM, Pasi Kärkkäinen wrote:
On Tue, Jan 23, 2018 at 06:20:39PM -0600, Kevin Stange wrote:
On 01/23/2018 05:57 PM, Karl Johnson wrote:
On Tue, Jan 23, 2018 at 4:50 PM, Nathan March <nathan@gt.net mailto:nathan@gt.net> wrote:
Hi, > Hmm.. isn't this the ldisc bug that was discussed a few months agoon this
list, > and a patch was applied to virt-sig kernel aswell? > > Call trace looks similar.. Good memory! I'd forgotten about that despite being the one who ran into it. Looks like that patch was just removed in 4.9.75-30 which I just upgraded this system to: http://cbs.centos.org/koji/buildinfo?buildID=21122 <http://cbs.centos.org/koji/buildinfo?buildID=21122> Previously I was on 4.9.63-29 which does not have this problem, anddoes
have the ldisc patch. So I guess the question is for Johnny, why was it removed? In the meantime, I'll revert the kernel and follow up if I see any further problems.IIRC the patch has been removed from the spec file because it has been merged upstream in 4.9.71.
The IRC discussion I found in my log indicates that it was removed because it didn't apply cleanly due to changes when updating to 4.9.75, yet I don't think anyone independently validated that the changes made are equivalent to the patch that was removed. I was never able to reproduce this issue, so I didn't investigate it myself.
Sounds like the patch is still needed :)
Anyone up to re-porting it to 4.9.75+ ?
It looked, at first glance, like 4.9.71 fixed it .. I guess not in all cases
I'm happy to do testing here if anyone's able to help with a patch, does look like reverting to 4.9.63-29 solved it for me in the interm.
Hello Nathan,
I noticed Upstream Linux now has some patches related to tty_ldisc .. as you seem to have an easily reproducible way of triggering the crashes, could you please try if these patches fix the issue, when applied to CentOS 4.9 kernel?
"tty: fix data race between tty_init_dev and flush of buf": https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/dr...
"tty: Avoid possible error pointer dereference at tty_ldisc_restore().": https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/dr...
"tty: Don't call panic() at tty_ldisc_init()": https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/dr...
"tty: Use __GFP_NOFAIL for tty_ldisc_get()": https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/dr...
Thanks,
-- Pasi