Re: [PATCH v2 4/5] workqueue: Show all busy workers in stall diagnostics
Jiri Slaby <[email protected]>
| Newsgroups | dev.linux.lists.regressions,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On 13. 05. 26, 9:29, Thorsten Leemhuis wrote: > On 5/11/26 07:21, Jiri Slaby wrote: >> we currently have several reports of this. On s390, ppc64, and x86_64. > > I stumbled on this by accident and this is not my area of expertise, so > the following might be bogus: > > Is this maybe the same as "Observed Workqueue lockups on offline CPUs.": > https://lore.kernel.org/lkml/[email protected]/ Thanks, looks like pretty much it. All three reports have: rcu: srcu_init: Setting srcu_struct sizes to big. > Fix is here: > https://lore.kernel.org/lkml/[email protected]/ Building a kernel with this and serving to the reporters to test. > Ciao, Thorsten > >> On 07. 05. 26, 15:11, Breno Leitao wrote: >>> Hi Jiri, >>> >>> On Thu, May 07, 2026 at 12:20:33PM +0200, Jiri Slaby wrote: >>>> On 05. 03. 26, 17:15, Breno Leitao wrote: >>>> >>>> BUG: workqueue lockup - pool cpus=144 node=0 flags=0x4 nice=0 >>>> stuck for >>>> 168224s! >>> >>> That's an extremely long stall (~1.95 days). >>> >>>> ... >>>> Showing busy workqueues and worker pools: >>>> workqueue rcu_gp: flags=0x108 >>>> pwq 578: cpus=144 node=0 flags=0x4 nice=0 active=3 refcnt=4 >>>> in: >>>> https://bugzilla.suse.com/show_bug.cgi?id=1263947 >>>> ? >>>> >>>> Can this (or other patch from the series) cause this? Should there be >>>> something like cpu_online() instead of task_is_running() somewhere? >>> >>> This series only affects stall reporting, not detection. The changes run >>> after the watchdog has identified a stall, so the detection logic itself >>> remains unchanged. >>> >>> To help diagnose this issue, could you provide some additional >>> information: >>> >>> 1) Was CPU 144 online at any point? If so, when was it taken offline? >> >> It was not, it's non-present. >> >>> 2) Does this message appear repeatedly? If you bring CPU 144 online, does >>> the issue resolve? >> >> Yes, look at this new x86_64 report's dmesg (I believe it is related to >> the above report): >> BUG: workqueue lockup - pool cpus=2 node=0 flags=0x4 nice=0 stuck for >> 50s! >> in: >> https://bugzilla.suse.com/attachment.cgi?id=890229 >> >> $ grep -c BUG sl.txt >> 504 >> $ grep -c pwq sl.txt >> 509 >> >> It comes from: >> https://bugzilla.suse.com/show_bug.cgi?id=1264554 >> >>> 3) Have you run similar tests on earlier kernel versions without seeing >>> this behavior, or is this a clear regression? >> >> It's new in 7.0. Going back to 6.19.12 makes it disappear. >> >> thanks, > -- js suse labs