On 04/18/2018 10:40 PM, Fengguang Wu wrote:
> [ 716.494065] PASS concurrent_autogo_5ghz_ht40 4.803608 2018-03-23 09:57:21.586794
> [ 716.494069]
> [ 716.496923] passed all 1 test case(s)
> [ 716.496926]
> [ 716.511702] swap_info_get: Bad swap file entry 04000000
> [ 716.512731] BUG: Bad page map in process python2 pte:100_0000_0000 pmd:17e8be067
> [ 716.513844] addr:00000000860ba23b vm_flags:00000070 anon_vma: (null) mapping:000000004c76fece index:1e2
> [ 716.515160] file:libpcre.so.3.13.3 fault:filemap_fault mmap:generic_file_mmap readpage:simple_readpage
> [ 716.516418] CPU: 2 PID: 8907 Comm: python2 Not tainted 4.16.0-rc5 #1
> [ 716.517533] Hardware name: /DH67GD, BIOS BLH6710H.86A.0132.2011.1007.1505 10/07/2011
Did you say that you have a few more examples of this?
I would be really interested if it's always python or always the same
shared library, or always file-backed memory, always the same bit,
etc... From the vm_flags, I'd guess that this is the "rw-p" part of the
file mapping.
The bit that gets set is really weird. It's bit 40. I could definitely
see scenarios where we might set the dirty bit, or even NX for that
matter, or some *bit* that we mess with in software. It's not even
close to the boundary where it could represent a swapoffset=1 or swapfile=1.
It's also unlikely to be _PAGE_PSE having gone missing from the PMD
since it's in the middle of a file-backed mapping and the PMD is
obviously pointing to a 4k page.
If I had to put money on it, I'd guess it's a hardware bit flip, or less
likely, a rogue software bit flip. But, more examples will hopefully
shed some more light.
Hi, Dave
I have met the same issue now but in 3.10.0-514.16.1.el7.x86_64, the
issue also accurred in last November.
I read 3.10.0-514.16.1.el7.x86_64, the bit9~13 is the swap type,
because the swap has been swapoff on my machine,
for the "Bad swap file entry" error, the bit9~13 should be zero, but
"Unused swap file entry" error is exist although the
bit9~13 is zero.
The lower 12 bits of pte is zero, and all abnormal ptes are serial in
a mmu page, so I guess the mmu page has been overwritten by someone.
The message details:
kernel: swap_free: Bad swap file entry 1000000000103256
kernel: BUG: Bad page map in process in:imjournal pte:8192b1000 pmd:3ff9324067
kernel: addr:00007f920adc5000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:3f8
kernel: vma->vm_ops->fault: shmem_fault+0x0/0x1d0
kernel: vma->vm_file->f_op->mmap: shmem_mmap+0x0/0x30
kernel: CPU: 5 PID: 9166 Comm: in:imjournal Tainted: G W OE
K------------ 3.10.0-514.16.1.el7.x86_64 #1
kernel: Hardware name: HP ProLiant DL380 Gen9/ProLiant DL380 Gen9,
BIOS P89 04/25/2017
kernel: 00007f920adc5000 0000000023409e11 ffff881fc769fc78 ffffffff81686ac3
kernel: ffff881fc769fcc0 ffffffff811acacf 00000008192b1000 00000000000003f8
kernel: ffff883ff9324e28 00000008192b1000 00007f920ae00000 00007f920adc5000
kernel: Call Trace:
kernel: [<ffffffff81686ac3>] dump_stack+0x19/0x1b
kernel: [<ffffffff811acacf>] print_bad_pte+0x1af/0x250
kernel: [<ffffffff811aea7b>] unmap_page_range+0x62b/0x8a0
kernel: [<ffffffff811aed71>] unmap_single_vma+0x81/0xf0
kernel: [<ffffffff811afc49>] unmap_vmas+0x49/0x90
kernel: [<ffffffff811b488e>] unmap_region+0xbe/0x140
kernel: [<ffffffff811b6c75>] do_munmap+0x245/0x420
kernel: [<ffffffff811b6e91>] vm_munmap+0x41/0x60
kernel: [<ffffffff811b7e22>] SyS_munmap+0x22/0x30
kernel: [<ffffffff81697189>] system_call_fastpath+0x16/0x1b
kernel: Disabling lock debugging due to kernel taint
kernel: swap_free: Bad swap file entry 3000000000006986
kernel: BUG: Bad page map in process in:imjournal pte:34c33000 pmd:3ff9324067
kernel: addr:00007f920adc6000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:3f9
kernel: vma->vm_ops->fault: shmem_fault+0x0/0x1d0
kernel: vma->vm_file->f_op->mmap: shmem_mmap+0x0/0x30
$ cat messages | grep swap_free
kernel: swap_free: Bad swap file entry 1000000000103256
kernel: swap_free: Bad swap file entry 3000000000006986
kernel: swap_free: Bad swap file entry 2000000000006986
kernel: swap_free: Unused swap file entry 00102e07
kernel: swap_free: Bad swap file entry 1000000000102e00
kernel: swap_free: Bad swap file entry 2000000000107fd0
kernel: swap_free: Bad swap file entry 2000000000006a88
kernel: swap_free: Bad swap file entry 3000000000103e67
kernel: swap_free: Bad swap file entry 300000000010324c
kernel: swap_free: Bad swap file entry 3000000000102e00
kernel: swap_free: Unused swap file entry 00102a56
kernel: swap_free: Unused swap file entry 00102ef5
kernel: swap_free: Bad swap file entry 3000000000102ef5
kernel: swap_free: Bad swap file entry 1000000000102a4f
kernel: swap_free: Bad swap file entry 3000000000103262
kernel: swap_free: Bad swap file entry 10000000001031c4
kernel: swap_free: Unused swap file entry 00006981
kernel: swap_free: Unused swap file entry 00006a88
kernel: swap_free: Bad swap file entry 3000000000102e00
kernel: swap_free: Bad swap file entry 3000000000102e08
kernel: swap_free: Unused swap file entry 000069d3
kernel: swap_free: Bad swap file entry 300000000010313a
kernel: swap_free: Unused swap file entry 0000699d
kernel: swap_free: Unused swap file entry 00006998
kernel: swap_free: Bad swap file entry 3000000000102e07
kernel: swap_free: Bad swap file entry 3000000000102e09
kernel: swap_free: Bad swap file entry 1000000000103174
kernel: swap_free: Bad swap file entry 2000000000102e76
kernel: swap_free: Bad swap file entry 1000000000102651
kernel: swap_free: Bad swap file entry 3000000000102efa
kernel: swap_free: Bad swap file entry 3000000000102d40
kernel: swap_free: Bad swap file entry 3000000000101cf5
kernel: swap_free: Bad swap file entry 10000000000069b5
kernel: swap_free: Bad swap file entry 100000000010264e
kernel: swap_free: Unused swap file entry 000069e8
kernel: swap_free: Bad swap file entry 20000000000069e8
kernel: swap_free: Bad swap file entry 20000000001021d2
kernel: swap_free: Unused swap file entry 0002e892
kernel: swap_free: Bad swap file entry 2000000000102a48
kernel: swap_free: Bad swap file entry 3000000000102dde
kernel: swap_free: Unused swap file entry 001027f2
kernel: swap_free: Bad swap file entry 200000000000ddf5
kernel: swap_free: Bad swap file entry 10000000000fd7e1
kernel: swap_free: Bad swap file entry 1000000000003215
kernel: swap_free: Bad swap file entry 10000000000f3555
kernel: swap_free: Bad swap file entry 20000000000f3555
kernel: swap_free: Bad swap file entry 20000000000fd494
kernel: swap_free: Bad swap file entry 30000000000fd494
kernel: swap_free: Bad swap file entry 10000000001027ec
kernel: swap_free: Bad swap file entry 1000000000103172
kernel: swap_free: Unused swap file entry 001039b2
kernel: swap_free: Unused swap file entry 001014da
kernel: swap_free: Bad swap file entry 20000000000fd8ea
kernel: swap_free: Bad swap file entry 100000000010036e
kernel: swap_free: Bad swap file entry 200000000010036e
kernel: swap_free: Bad swap file entry 30000000000f6ced
kernel: swap_free: Bad swap file entry 3000000000006a8f
kernel: swap_free: Bad swap file entry 2000000000102e2a
kernel: swap_free: Bad swap file entry 1000000000107bc5
$ cat messages | grep pmd
kernel: BUG: Bad page map in process in:imjournal pte:8192b1000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:34c33000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:34c32000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:81703c000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:817001000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:83fe82000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:35442000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:81f33b000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:819263000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:817007000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:8152b0000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:8177a8000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:8177ab000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:815279000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:819317000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:818e25000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:34c0c000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:35440000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:817003000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:817047000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:34e98000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:8189d3000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:34cec000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:34cc0000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:81703f000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:81704b000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:818ba5000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:8173b6000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:81328d000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:8177d3000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:816a03000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:80e7af000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:34da9000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:813271000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:34f40000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:34f42000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:810e92000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:174494000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:815242000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:816ef7000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:813f90000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:6efae000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:7ebf0d000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:190ad000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:79aaa9000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:79aaaa000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:7ea4a6000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:7ea4a7000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:813f61000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:818b91000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:81cd94000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:80a6d4000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:7ec752000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:801b75000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:801b76000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:7b676f000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:3547b000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:817152000 pmd:3ff9324067
kernel: BUG: Bad page map in process in:imjournal pte:83de29000 pmd:3ff9324067
$ cat messages | grep addr
kernel: addr:00007f920adc5000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:3f8
kernel: addr:00007f920adc6000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:3f9
kernel: addr:00007f920adc7000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:3fa
kernel: addr:00007f920adc8000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:3fb
kernel: addr:00007f920adc9000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:3fc
kernel: addr:00007f920adca000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:3fd
kernel: addr:00007f920adcb000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:3fe
kernel: addr:00007f920adcc000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:3ff
kernel: addr:00007f920adcd000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:400
kernel: addr:00007f920adce000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:401
kernel: addr:00007f920adcf000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:402
kernel: addr:00007f920add0000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:403
kernel: addr:00007f920add1000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:404
kernel: addr:00007f920add2000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:405
kernel: addr:00007f920add3000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:406
kernel: addr:00007f920add4000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:407
kernel: addr:00007f920add5000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:408
kernel: addr:00007f920add6000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:409
kernel: addr:00007f920add7000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:40a
kernel: addr:00007f920add8000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:40b
kernel: addr:00007f920add9000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:40c
kernel: addr:00007f920adda000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:40d
kernel: addr:00007f920addb000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:40e
kernel: addr:00007f920addc000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:40f
kernel: addr:00007f920addd000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:410
kernel: addr:00007f920adde000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:411
kernel: addr:00007f920addf000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:412
kernel: addr:00007f920ade0000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:413
kernel: addr:00007f920ade1000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:414
kernel: addr:00007f920ade2000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:415
kernel: addr:00007f920ade3000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:416
kernel: addr:00007f920ade4000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:417
kernel: addr:00007f920ade5000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:418
kernel: addr:00007f920ade6000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:419
kernel: addr:00007f920ade7000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:41a
kernel: addr:00007f920ade8000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:41b
kernel: addr:00007f920ade9000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:41c
kernel: addr:00007f920adea000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:41d
kernel: addr:00007f920adeb000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:41e
kernel: addr:00007f920adec000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:41f
kernel: addr:00007f920aded000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:420
kernel: addr:00007f920adee000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:421
kernel: addr:00007f920adef000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:422
kernel: addr:00007f920adf0000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:423
kernel: addr:00007f920adf1000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:424
kernel: addr:00007f920adf2000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:425
kernel: addr:00007f920adf3000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:426
kernel: addr:00007f920adf4000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:427
kernel: addr:00007f920adf5000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:428
kernel: addr:00007f920adf6000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:429
kernel: addr:00007f920adf7000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:42a
kernel: addr:00007f920adf8000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:42b
kernel: addr:00007f920adf9000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:42c
kernel: addr:00007f920adfa000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:42d
kernel: addr:00007f920adfb000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:42e
kernel: addr:00007f920adfc000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:42f
kernel: addr:00007f920adfd000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:430
kernel: addr:00007f920adfe000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:431
kernel: addr:00007f920adff000 vm_flags:080000d1 anon_vma:
(null) mapping:ffff883fe5284960 index:432
Thanks.
Huaitong Han
2018-04-20 2:53 GMT+08:00 Dave Hansen <[email protected]>:
> On 04/18/2018 10:40 PM, Fengguang Wu wrote:
>> [ 716.494065] PASS concurrent_autogo_5ghz_ht40 4.803608 2018-03-23 09:57:21.586794
>> [ 716.494069]
>> [ 716.496923] passed all 1 test case(s)
>> [ 716.496926]
>> [ 716.511702] swap_info_get: Bad swap file entry 04000000
>> [ 716.512731] BUG: Bad page map in process python2 pte:100_0000_0000 pmd:17e8be067
>> [ 716.513844] addr:00000000860ba23b vm_flags:00000070 anon_vma: (null) mapping:000000004c76fece index:1e2
>> [ 716.515160] file:libpcre.so.3.13.3 fault:filemap_fault mmap:generic_file_mmap readpage:simple_readpage
>> [ 716.516418] CPU: 2 PID: 8907 Comm: python2 Not tainted 4.16.0-rc5 #1
>> [ 716.517533] Hardware name: /DH67GD, BIOS BLH6710H.86A.0132.2011.1007.1505 10/07/2011
>
> Did you say that you have a few more examples of this?
>
> I would be really interested if it's always python or always the same
> shared library, or always file-backed memory, always the same bit,
> etc... From the vm_flags, I'd guess that this is the "rw-p" part of the
> file mapping.
>
> The bit that gets set is really weird. It's bit 40. I could definitely
> see scenarios where we might set the dirty bit, or even NX for that
> matter, or some *bit* that we mess with in software. It's not even
> close to the boundary where it could represent a swapoffset=1 or swapfile=1.
>
> It's also unlikely to be _PAGE_PSE having gone missing from the PMD
> since it's in the middle of a file-backed mapping and the PMD is
> obviously pointing to a 4k page.
>
> If I had to put money on it, I'd guess it's a hardware bit flip, or less
> likely, a rogue software bit flip. But, more examples will hopefully
> shed some more light.
>
On 05/02/2018 08:20 PM, Huaitong Han wrote:
>
> kernel: swap_free: Bad swap file entry 1000000000103256
> kernel: BUG: Bad page map in process in:imjournal pte:8192b1000 pmd:3ff9324067
> kernel: addr:00007f920adc5000 vm_flags:080000d1 anon_vma:
> (null) mapping:ffff883fe5284960 index:3f8
> kernel: vma->vm_ops->fault: shmem_fault+0x0/0x1d0
> kernel: vma->vm_file->f_op->mmap: shmem_mmap+0x0/0x30
> kernel: CPU: 5 PID: 9166 Comm: in:imjournal Tainted: G W OE
> K------------ 3.10.0-514.16.1.el7.x86_64 #1
This looks like an entirely different signature. There are lots of bits
set in the bad swap entry instead of a single one. It's also a vintage
RHEL kernel, not mainline.