On Aug 10, 2023, at 6:55 PM, Guenter Roeck linux@roeck-us.net wrote:
On 8/10/23 14:54, Joel Fernandes wrote:
On Thu, Aug 10, 2023 at 10:55:16AM -0700, Paul E. McKenney wrote: On Wed, Aug 09, 2023 at 02:45:44PM -0700, Guenter Roeck wrote:
On 8/9/23 13:39, Joel Fernandes wrote:
On Wed, Aug 9, 2023 at 4:38 PM Guenter Roeck linux@roeck-us.net wrote:
On 8/9/23 13:14, Joel Fernandes wrote: > On Wed, Aug 09, 2023 at 12:25:48PM -0700, Guenter Roeck wrote: >> On Wed, Aug 09, 2023 at 02:35:59PM -0400, Joel Fernandes wrote: >>> On Wed, Aug 9, 2023 at 12:18 PM Guenter Roeck linux@roeck-us.net wrote: >>>> >>>> On 8/9/23 06:53, Joel Fernandes wrote: >>>>> On Wed, Aug 09, 2023 at 12:40:36PM +0200, Greg Kroah-Hartman wrote: >>>>>> This is the start of the stable review cycle for the 5.15.126 release. >>>>>> There are 92 patches in this series, all will be posted as a response >>>>>> to this one. If anyone has any issues with these being applied, please >>>>>> let me know. >>>>>> >>>>>> Responses should be made by Fri, 11 Aug 2023 10:36:10 +0000. >>>>>> Anything received after that time might be too late. >>>>>> >>>>>> The whole patch series can be found in one patch at: >>>>>> https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.126-rc... >>>>>> or in the git tree and branch at: >>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y >>>>>> and the diffstat can be found below. >>>>> >>>>> Not necesscarily new with 5.15 stable but 3 of the 19 rcutorture scenarios >>>>> hang with this -rc: TREE04, TREE07, TASKS03. >>>>> >>>>> 5.15 has a known stop machine issue where it hangs after 1.5 hours with cpu >>>>> hotplug rcutorture testing. Me and tglx are continuing to debug this. The >>>>> issue does not show up on anything but 5.15 stable kernels and neither on >>>>> mainline. >>>>> >>>> >>>> Do you by any have a crash pattern that we could possibly use to find the crash >>>> in ChromeOS crash logs ? No idea if that would help, but it could provide some >>>> additional data points. >>> >>> The pattern shows as a hard hang, the system is unresponsive and all CPUs >>> are stuck in stop_machine. Sometimes it recovers on its own from the >>> hang and then RCU immediately gives stall warnings. It takes 1.5 hour >>> to reproduce and sometimes never happens for several hours. >>> >>> It appears related to CPU hotplug since gdb showed me most of the CPUs >>> are spinning in multi_cpu_stop() / stop machine after the hang. >>> >> >> Hmm, we do see lots of soft lockups with multi_cpu_stop() in the backtrace, >> but not with v5.15.y but with v5.4.y. The actual hang is in stop_machine_yield(). > > Interesting. It looks similar as far as the stack dump in gdb goes, here are > the stacks I dumped with the hang I referred to: > https://paste.debian.net/1288308/ >
That link gives me "Entry not found".
Yeah that was weird. Here it is again: https://pastebin.com/raw/L3nv1kH2
I found a couple of crash reports from chromeos-5.10, one of them complaining about RCU issues. I sent you links via IM. Nothing from 5.15 or later, though.
Is the crash showing the eternally refiring timer fixed by this commit?
53e87e3cdc15 ("timers/nohz: Last resort update jiffies on nohz_full IRQ entry")
Ah I was just replying, I have been seeing really good results after applying the following 3 commits since yesterday: 53e87e3cdc15 ("timers/nohz: Last resort update jiffies on nohz_full IRQ entry") 5417ddc1cf1f ("timers/nohz: Switch to ONESHOT_STOPPED in the low-res handler when the tick is stopped") a1ff03cd6fb9 ("tick: Detect and fix jiffies update stall")
Would those also apply to v5.10.y, or just 5.15.y ?
All apply to 5.10 but one. I am currently testing with it more and will post to stable for 5.10 as well.
Thanks,
- Joel
Thanks, Guenter
5417ddc1cf1f also mentioned a "tick storm" which is exactly what I was seeing. I did a lengthy test and everything is looking good. I'll send these out to the stable list. thanks,
- Joel