Re: unused swap offset / bad page map.

[Dave Jones <davej@redhat.com>]

On Mon, Aug 26, 2013 at 11:45:53AM +0800, Hillf Danton wrote:
 > On Fri, Aug 23, 2013 at 11:53 AM, Dave Jones <davej@redhat.com> wrote:
 > >
 > > It actually seems worse, seems I can trigger it even easier now, as if
 > > there's a leak.
 > >
 > Can you please try the new fix for TLB flush?
 > 
 > commit  2b047252d087be7f2ba
 > Fix TLB gather virtual address range invalidation corner cases

No luck.

[ 4588.541886] swap_free: Unused swap offset entry 00002d15
[ 4588.541952] BUG: Bad page map in process trinity-kid12  pte:005a2a80 pmd:22c01f067
[ 4588.541979] addr:00007f0e95fa8000 vm_flags:00100073 anon_vma:ffff880217665550 mapping:          (null) index:1a42
[ 4588.542011] Modules linked in: snd_seq_dummy fuse hidp bnep scsi_transport_iscsi rfcomm ipt_ULOG can_bcm can_raw nfnetlink nfc caif_socket caif af_802154 phonet af_rxrpc bluetooth rfkill can llc2 pppoe pppox ppp_generic slhc irda crc_ccitt rds af_key rose x25 atm netrom appletalk ipx p8023 psnap p8022 llc ax25 xfs libcrc32c snd_hda_codec_realtek snd_hda_intel e1000e snd_hda_codec snd_hwdep ptp snd_seq snd_seq_device snd_pcm usb_debug pps_core pcspkr snd_page_alloc snd_timer snd soundcore
[ 4588.542245] CPU: 2 PID: 25390 Comm: trinity-kid12 Not tainted 3.11.0-rc7+ #13 
[ 4588.542321]  0000000000000000 ffff88021ba33c98 ffffffff816f9ddf 00007f0e95fa8000
[ 4588.542354]  ffff88021ba33ce0 ffffffff81177047 00000000005a2a80 0000000000001a42
[ 4588.542386]  00007f0e96000000 ffff88022c01fd40 00000000005a2a80 ffff88021ba33e00
[ 4588.542418] Call Trace:
[ 4588.542435]  [<ffffffff816f9ddf>] dump_stack+0x54/0x74
[ 4588.542457]  [<ffffffff81177047>] print_bad_pte+0x187/0x220
[ 4588.542478]  [<ffffffff81178874>] unmap_single_vma+0x524/0x850
[ 4588.542500]  [<ffffffff81179ac9>] unmap_vmas+0x49/0x90
[ 4588.542521]  [<ffffffff811822c5>] exit_mmap+0xc5/0x170
[ 4588.542542]  [<ffffffff8104ffb7>] mmput+0x77/0x100
[ 4588.542562]  [<ffffffff8105465d>] do_exit+0x28d/0xcd0
[ 4588.542583]  [<ffffffff810c0085>] ? trace_hardirqs_on_caller+0x115/0x1e0
[ 4588.542607]  [<ffffffff810c015d>] ? trace_hardirqs_on+0xd/0x10
[ 4588.542629]  [<ffffffff8105643c>] do_group_exit+0x4c/0xc0
[ 4588.543534]  [<ffffffff810564c4>] SyS_exit_group+0x14/0x20
[ 4588.544438]  [<ffffffff8170d554>] tracesys+0xdd/0xe2

I can reproduce this pretty quickly by driving the system into swapping using
a few instances of 'trinity -C64' (this creates 64 threads) 

I'm not sure how far back this bug goes, so I'll try some older kernels
and see if I can bisect it, because we don't seem to be getting closer
to figuring out what's actually happening..

	Dave

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