On Tue, Jun 12, 2018 at 9:33 PM, Roman Gushchin <g...@fb.com> wrote: > On Tue, Jun 12, 2018 at 09:08:27PM -0700, John Stultz wrote: >> On Tue, Jun 12, 2018 at 6:02 PM, John Stultz <john.stu...@linaro.org> wrote: >> > Hey Tejun, >> > With the current linus/master, I'm able to fairly regularly trip >> > OOPSes (two examples below) in mem_cgroup_protected(), which seems to >> > be new. I haven't managed to trigger this sort of thing with v4.17. >> > >> > I've not had much time to dig in or bisect it - I only know that >> > enabling most of the memory debuging config options didn't seem to >> > trip anything prior to the issue. So I wanted to send you a heads up >> > to see if there was already known, or if there was anything you might >> > suggest to help chase this down. >> >> >> So the line where we're crashing seems to be in mem_cgroup_protected(): >> parent_emin = READ_ONCE(parent->memory.emin); >> >> where I'm guessing the parent->memory value is null, and emin is at >> the 0x120 offset in the strucutre. >> >> Reverting the following commits seems to avoid the issue. >> bf8d5d52ffe8 ("memcg: introduce memory.min") >> 5f93ad67436b ("mm: treat memory.low value inclusive") >> 230671533d64 ("mm: memory.low hierarchical behavior") >> >> I'm guessing I'm tripping over some path where the memory value never >> gets initialized? >> >> Any ideas or suggestions? > > Hi, John! > > The patch below should fix the problem. > It's in the mm tree right now, and hopefully will be merged upstream asap. > Sorry for the inconvenience.
No worries, thanks for the quick fix! The patch you sent seems to be working well! Thanks again! -john