Re: [PATCH v2 4/5] workqueue: Show all busy workers in stall diagnostics
Thorsten Leemhuis <[email protected]>
| Newsgroups | dev.linux.lists.regressions,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
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]/ Fix is here: https://lore.kernel.org/lkml/[email protected]/ 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,