The kernel has several widespread bugs that are affecting all releases, that are impacting a lot of users.
* Hibernation There are so many bugs here it's hard to know where to begin. - We have cases where it fails to sleep, or resumes instantly. - There are cases where it looks to be working ok, but shortly after resuming, we see oopses/panics etc. It looks like something is scribbling over random parts of memory (usually landing on the dcache) - For some of those cases, it's an i915 bug where disabling modesetting works around it. We've seen similar bugs from non-i915 hardware though.
* Root dentry has weird name <> A number of users are seeing this message, which again, looks like something scribbled over the dcache. Some, but not all were using hibernate, so we have possibly another case of kernel memory corruption. (or perhaps resuming from hibernate makes this bug easier to hit)
* Page table corruption. We have an alarming number of reports from users seeing 'bad page map' or 'bad page entry' messages from the kernel. There's no real pattern here that we can see.
We have a number of ideas to try and further diagnose this, which we'll discuss at 18:00UTC today, in our bi-weekly kernel meeting in #fedora-meeting.
Dave
Dave (and others),
The kernel has several widespread bugs that are affecting all releases, that are impacting a lot of users.
- Hibernation There are so many bugs here it's hard to know where to begin.
- We have cases where it fails to sleep, or resumes instantly.
- There are cases where it looks to be working ok, but shortly after resuming, we see oopses/panics etc. It looks like something is scribbling over random parts of memory (usually landing on the dcache)
- For some of those cases, it's an i915 bug where disabling modesetting works around it. We've seen similar bugs from non-i915 hardware though.
Since about 3.0, I have been collecting - rather patiently - various hibernate-related kernel errors (I have about 8-9) and could email/send these if there is interest. I have also been logging various hibernate-related bugs with bugzilla for the past year or so.
This problem is the only one I have been experiencing with the kernel, but it has been going on for quite a while (since F8, I think - hibernate was an unmitigated disaster then). Admittedly, hibernate/restore is much more stable now, but nearly not stable-enough so that I could be confident to get to my desktop when I power up my PC after hibernate is done.
The machine I use hibernate on takes quite a hammering on a daily basis (it is on for at least 75 hours a week as most of my development work is done there) and it is very annoying when restore after hibernate fails and I have to start all over again. It does not happen as often as before, but it is not very stable either.
From my experience, I think the root of the problem is swap page/memory corruption during or shortly after hibernate/restore cycle. I was planning to allocate a separate partition on the hard disk just for hibernate, instead of using the swap partition as is the case now, to see whether the instability I am experiencing will go away.
Another issue I started experiencing just recently (since version 3.1 of the kernel was installed) - when I initiate hibernate, my PC powers down normally, but as soon as I switch my monitor off (press the off switch on the monitor itself), the computer starts up straight away! If I wait a while for the monitor to switch off "naturally" (i.e. after it switches off when it is not getting a video signal from the PC for about 10 seconds) then when I switch it off the PC stays off. Bizarre!
I did not experience this before and I am not sure whether the fact that I have usb hub on that monitor (which I do use) has anything to do with this rather peculiar behaviour.
Again, this seems unique to kernel versions 3.1 and above and I haven't changed my BIOS or anything on my configuration at all.
Just my 2p worth.
kernel@lists.fedoraproject.org
-
Dave Jones -
Mr Dash Four