[PATCH] Cover letter for (PCI/AER: only insert one element into kfifo)

[Yanjiang Jin]

Without this patch, if we have multi PCIe devices, and one of them has
AER error, aer_recover_work_func() -> kfifo_get() will traverse the whole
kfifo which has wrong element number(16).
If one null element's uninitialized memory matches another
PCIe device(0000:01:00.0), we may get the below call trace.
It is unusual, but indeed happened on my board: QDF2400.

# lspci
0000:00:00.0 PCI bridge:
0000:01:00.0 Ethernet controller:
0004:00:00.0 PCI bridge:
0004:01:00.0 Ethernet controller:
0005:00:00.0 PCI bridge:
0005:01:00.0 Ethernet controller:

Call trace:

[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 5
[Hardware Error]: It has been corrected by h/w and requires no further action
[Hardware Error]: event severity: corrected
[Hardware Error]:  precise tstamp: 2018-11-29 09:23:16
[Hardware Error]:  Error 0, type: corrected
[Hardware Error]:   section_type: PCIe error
[Hardware Error]:   port_type: 4, root port
[Hardware Error]:   version: 3.0
[Hardware Error]:   command: 0x0407, status: 0x0010
[Hardware Error]:   device_id: 0004:00:00.0
[Hardware Error]:   slot: 0
[Hardware Error]:   secondary_bus: 0x01
[Hardware Error]:   vendor_id: 0x17cb, device_id: 0x0401
[Hardware Error]:   class_code: 000406
[Hardware Error]:   bridge: secondary_status: 0x0000, control: 0x0000
AER recover: find pci_dev for 0004:00:00:0
pcieport 0004:00:00.0: aer_status: 0x00000001, aer_mask: 0x0000e000
pcieport 0004:00:00.0:    [ 0] RxErr                  (First)
pcieport 0004:00:00.0: aer_layer=Physical Layer, aer_agent=Receiver ID
AER recover: Can not find pci_dev for a38f:00:18:2
AER recover: Can not find pci_dev for 0857:1c:03:5
AER recover: Can not find pci_dev for 62d2:80:19:6
AER recover: Can not find pci_dev for 0857:f8:03:4
AER recover: Can not find pci_dev for 0907:78:07:1
AER recover: Can not find pci_dev for 0000:00:00:1
AER recover: Can not find pci_dev for 0907:00:00:0
AER recover: Can not find pci_dev for 0000:00:00:1
AER recover: find pci_dev for 0000:01:00:0
Unable to handle kernel paging request at virtual address 0000000000813004
Mem abort info:
  ESR = 0x96000007
  Exception class = DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
Data abort info:
  ISV = 0, ISS = 0x00000007
  CM = 0, WnR = 0
user pgtable: 64k pages, 48-bit VAs, pgdp = 000000000dce9024
[0000000000813004] pgd=0000001727260003, pud=0000001727260003
pmd=0000001727290003, pte=0000000000000000
Internal error: Oops: 96000007 [#1] SMP
Workqueue: events aer_recover_work_func
pstate: 20400005 (nzCv daif +PAN -UAO)
pc : cper_print_aer+0x4c/0x290
lr : aer_recover_work_func+0x110/0x150
sp : ffff8017ca59fca0
x29: ffff8017ca59fca0 x28: ffff8017ca841000
x27: ffff8017ca841000 x26: 0000000000000001
x25: 0000000000813000 x24: 0000000000000040
x23: 0000000000000040 x22: ffff000008d5f830
x21: ffff0000090f1f10 x20: ffff0000090f1e98
x19: 0000000000000000 x18: ffffffffffffffff
x17: 0000000000000001 x16: 0000000000000007
x15: ffff000009073708 x14: ffff0000891e8faf
x13: ffff0000091e8fbd x12: 2c726579614c206c
x11: ffff00000909b000 x10: 0000000005f5e0ff
x9 : ffff8017ca59fa10 x8 : ffff000009073978
x7 : ffff0000091e8a40 x6 : 0000000000000518
x5 : 0000000000000001 x4 : ffff8017ff9710b8
x3 : ffff8017ff9710b8 x2 : 0000000000813000
x1 : 0000000000000000 x0 : ffff000009073708
Process kworker/11:1 (pid: 232, stack limit = 0x00000000060ad7e1)
Call trace:
 cper_print_aer+0x4c/0x290
 aer_recover_work_func+0x110/0x150
 process_one_work+0x1ac/0x3f0
 worker_thread+0x54/0x430
 kthread+0x104/0x130
 ret_from_fork+0x10/0x18
Code: f9400001 f90057a1 d2800001 54000f40 (2940e334)
SMP: stopping secondary CPUs
Starting crashdump kernel...
Bye!



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