On Thu, Dec 10, 2015 at 04:30:24PM -0500, Chris Mason wrote:
> On Thu, Dec 10, 2015 at 02:35:55PM -0500, Dave Jones wrote:
> > On Thu, Dec 10, 2015 at 02:02:20PM -0500, Chris Mason wrote:
> > > On Tue, Dec 08, 2015 at 11:25:28PM -0500, Dave Jones wrote:
> > > > Not sure if I've already reported this one, but I've been seeing this
> > > > a lot this last couple days.
> > > >
> > > > kernel BUG at mm/page-writeback.c:2654!
> > > > invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN
> > > > CPU: 1 PID: 2566 Comm: trinity-c1 Tainted: G W
> > 4.4.0-rc4-think+ #14
> > > > task: ffff880462811b80 ti: ffff8800cd808000 task.ti: ffff8800cd808000
> > > > RIP: 0010:[<ffffffff8826ff40>] [<ffffffff8826ff40>]
> > clear_page_dirty_for_io+0x180/0x1d0
> > >
> > > Huh, are you able to reproduce at will? From this code path it should
> > > mean somebody else is unlocking a page they don't own.
> >
> > pretty easily yeah. I hit it maybe a couple dozen times yesterday.
> > So if you've got some idea of printk's to spray anywhere I can give
> > that a shot.
>
> I'd rather try to trigger it here. Going to have to add some way to
> record which stack trace last unlocked and/or freed the page.
perhaps a clue.. this is the log fragment from the last trinity run..
[child4:1416] [25] splice(fd_in=257, off_in=0x0, fd_out=257, off_out=0x0,
len=0xe000, flags=0x0) = -1 (Invalid argument)
[child4:1416] [26] pwrite64(fd=257, buf=0x2253530, count=782, pos=0x40404000)
[child5:1414] [28] semop(semid=-16274, tsops=0x0, nsops=0x2000000000c6b4d5) =
-1 (Invalid argument)
[child5:1414] [29] mlockall(flags=0x1)
[child6:1427] [50] getgid() = 1000
[child6:1427] [51] mlock(addr=0x7f4c00d62000, len=0)
[child7:1402] [79] setuid(uid=0x790617fe) = -1 (Invalid argument)
[child7:1402] [80] write(fd=257, buf=0x2255d90, count=2296)
the oops I got was in write(), so it looked like a parallel write() with
pwrite() was the trigger.
Sure enough, doing a run with -c write -c pwrite64 reproduces it even faster.
Dave
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