Did some preliminary investigation on this one.
The problem is the cc->freepages list is empty, but cc->nr_freepages >
0, it looks the list and nr_freepages get out-of-sync somewhere.
Any hint is appreciated.
Thanks,
Yang
On 4/21/2016 5:38 PM, Shi, Yang wrote:
Hi folks,
I did the below test with huge tmpfs on linux-next-20160420:
# mount -t tmpfs huge=1 tmpfs /mnt
# cd /mnt
Then clone linux kernel
Then I got the below bug, such test works well on non-huge tmpfs.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff8119d2f8>] release_freepages+0x18/0xa0
PGD 0
Oops: 0000 [#1] PREEMPT SMP
Modules linked in:
CPU: 6 PID: 110 Comm: kcompactd0 Not tainted
4.6.0-rc4-next-20160420-WR7.0.0.0_standard #4
Hardware name: Intel Corporation S5520HC/S5520HC, BIOS
S5500.86B.01.10.0025.030220091519 03/02/2009
task: ffff880361708040 ti: ffff880361704000 task.ti: ffff880361704000
RIP: 0010:[<ffffffff8119d2f8>] [<ffffffff8119d2f8>]
release_freepages+0x18/0xa0
RSP: 0018:ffff880361707cf8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88036ffde7c0 RCX: 0000000000000009
RDX: 0000000000001bf1 RSI: 000000000000000f RDI: ffff880361707dd0
RBP: ffff880361707d20 R08: 0000000000000007 R09: 0000160000000000
R10: ffff88036ffde7c0 R11: 0000000000000000 R12: 0000000000000000
R13: ffff880361707dd0 R14: ffff880361707dc0 R15: ffff880361707db0
FS: 0000000000000000(0000) GS:ffff880363cc0000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000002206000 CR4: 00000000000006e0
Stack:
ffff88036ffde7c0 0000000000000000 0000000000001a00 ffff880361707dc0
ffff880361707db0 ffff880361707da0 ffffffff8119f13d ffffffff81196239
0000000000000000 ffff880361708040 0000000000000001 0000000000100000
Call Trace:
[<ffffffff8119f13d>] compact_zone+0x55d/0x9f0
[<ffffffff81196239>] ? fragmentation_index+0x19/0x70
[<ffffffff8119f92f>] kcompactd_do_work+0x10f/0x230
[<ffffffff8119fae0>] kcompactd+0x90/0x1e0
[<ffffffff810a3a40>] ? wait_woken+0xa0/0xa0
[<ffffffff8119fa50>] ? kcompactd_do_work+0x230/0x230
[<ffffffff810801ed>] kthread+0xdd/0x100
[<ffffffff81be5ee2>] ret_from_fork+0x22/0x40
[<ffffffff81080110>] ? kthread_create_on_node+0x180/0x180
Code: c1 fa 06 31 f6 e8 a9 9b fd ff eb 98 0f 1f 80 00 00 00 00 66 66 66
66 90 55 48 89 e5 41 57 41 56 41 55 49 89 fd 41 54 53 48 8b 07 <48> 8b
10 48 8d 78 e0 49 39 c5 4c 8d 62 e0 74 70 49 be 00 00 00
RIP [<ffffffff8119d2f8>] release_freepages+0x18/0xa0
RSP <ffff880361707cf8>
CR2: 0000000000000000
---[ end trace 855da7e142f7311f ]---
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