Messages in this thread | | | Subject | Re: 4.4: INFO: rcu_sched self-detected stall on CPU | From | Boris Ostrovsky <> | Date | Wed, 30 Mar 2016 09:44:49 -0400 |
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On 03/29/2016 02:04 PM, Steven Haigh wrote: > Greg, please see below - this is probably more for you... > > On 03/29/2016 04:56 AM, Steven Haigh wrote: >> Interestingly enough, this just happened again - but on a different >> virtual machine. I'm starting to wonder if this may have something to do >> with the uptime of the machine - as the system that this seems to happen >> to is always different. >> >> Destroying it and monitoring it again has so far come up blank. >> >> I've thrown the latest lot of kernel messages here: >> http://paste.fedoraproject.org/346802/59241532 > So I just did a bit of digging via the almighty Google. > > I started hunting for these lines, as they happen just before the stall: > BUG: Bad rss-counter state mm:ffff88007b7db480 idx:2 val:-1 > BUG: Bad rss-counter state mm:ffff880079c638c0 idx:0 val:-1 > BUG: Bad rss-counter state mm:ffff880079c638c0 idx:2 val:-1 > > I stumbled across this post on the lkml: > http://marc.info/?l=linux-kernel&m=145141546409607 > > The patch attached seems to reference the following change in > unmap_mapping_range in mm/memory.c: >> - struct zap_details details; >> + struct zap_details details = { }; > When I browse the GIT tree for 4.4.6: > https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/mm/memory.c?id=refs/tags/v4.4.6 > > I see at line 2411: > struct zap_details details; > > Is this something that has been missed being merged into the 4.4 tree? > I'll admit my kernel knowledge is not enough to understand what the code > actually does - but the similarities here seem uncanny.
The patch that you are referring to is trying to fix a bug in a feature that's not in the mainline yet ("mm, oom: introduce oom reaper").
-boris
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