On Thu, Nov 09, 2023 at 10:14:22AM +0100, Christian Theune via Openipmi-developer wrote: > Hi, > > > > > On 3. Oct 2023, at 07:13, Corey Minyard <miny...@acm.org> wrote: > > > > Yeah, I understand how this would be a strange scenario. I have seen > > this happen in the real world, so it is something that's possible, but I > > think the printk changes went in before 5.10. > > > > Maybe a firmware update to the BMC? I think you would have mentioned > > that, though. > > do you know how to reproduce this error? I’ve disabled SOL logging on one of > the affected machines (it might be related to the specific BMC and I’m > considering BMC firmware updates) but I’ve spammed the kmsg that are sent to > the SOL for 12+ hours in a tight bash loop without an SOL attached and did > not trigger the issue…
I believe you have to call printk from some sort of atomic context, like an interrupt or with preemption disabled. Then, on an SMP system, it would have to somehow block the running of the thread of execution you care about. > > Next to the BMC firmware update I’m also considering switching from 5.10 to > 5.15 (we’re having issues in 6.1 at the moment so I don’t want to go there > right now) but I’d love if I could construct a reproducer … > > Unfortunately the BMC firmwares do not show changelogs and I’m a bit wary of > thinking that a BMC issue would be the culprit here … -_- I'd agree, it doesn't really seem so, and even if it is, it doesn't really matter. > > I also didn’t find the original commit that you mentioned would be fixing it > … a hint for what to search for in the changelogs would be much appreciated! It's 09c5ba0aa2fc "printk: add kthread console printers" and some others. It's in 5.19, so it was later than I thought. I'm not being a lot of help here, but hopefully it can lead you somewhere you can figure this out. These can be hard problems to track down. I don't remember, had you done anything with the kernel preempt tracing? That can be useful for tracking down long preempt off times. -corey > > Kind regards, > Christian _______________________________________________ Openipmi-developer mailing list Openipmi-developer@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openipmi-developer
