linux/arch/s390/pci
Niklas Schnelle 3047766bc6 s390/pci: fix enabling a reserved PCI function
In usual IPL or hot plug scenarios a zPCI function transitions directly
from reserved (invisible to Linux) to configured state or is configured
by Linux itself using an SCLP, however it can also first go from
reserved to standby and then from standby to configured without
Linux initiative.
In this scenario we first get a PEC event 0x302 and then 0x301.  This may
happen for example when the device is deconfigured at another LPAR and
made available for this LPAR. It may also happen under z/VM when
a device is attached while in some inconsistent state.

However when we get the 0x301 the device is already known to zPCI
so calling zpci_create() will add it twice resulting in the below
BUG. Instead we should only enable the existing device and finally
scan it through the PCI subsystem.

list_add double add: new=00000000ed5a9008, prev=00000000ed5a9008, next=0000000083502300.
kernel BUG at lib/list_debug.c:31!
Krnl PSW : 0704c00180000000 0000000082dc2db8 (__list_add_valid+0x70/0xa8)
Call Trace:
 [<0000000082dc2db8>] __list_add_valid+0x70/0xa8
([<0000000082dc2db4>] __list_add_valid+0x6c/0xa8)
 [<00000000828ea920>] zpci_create_device+0x60/0x1b0
 [<00000000828ef04a>] zpci_event_availability+0x282/0x2f0
 [<000000008315f848>] chsc_process_crw+0x2b8/0xa18
 [<000000008316735c>] crw_collect_info+0x254/0x348
 [<00000000829226ea>] kthread+0x14a/0x168
 [<000000008319d5c0>] ret_from_fork+0x24/0x2c

Fixes: f606b3ef47 ("s390/pci: adapt events for zbus")
Reported-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Tested-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2020-06-29 16:26:28 +02:00
..
Makefile s390/pci: create zPCI bus 2020-04-28 13:49:46 +02:00
pci.c s390/pci: ioremap() align with generic code 2020-05-20 10:22:52 +02:00
pci_bus.c s390/pci: create links between PFs and VFs 2020-05-20 10:22:51 +02:00
pci_bus.h s390/pci: Handling multifunctions 2020-04-28 13:49:47 +02:00
pci_clp.c s390/pci: Log new handle in clp_disable_fh() 2020-05-28 12:26:03 +02:00
pci_debug.c locking/atomic, s390/pci: Remove redundant casts 2019-06-03 12:32:57 +02:00
pci_dma.c dma-mapping updates for 5.4: 2019-09-19 13:27:23 -07:00
pci_event.c s390/pci: fix enabling a reserved PCI function 2020-06-29 16:26:28 +02:00
pci_insn.c s390/pci: provide support for MIO instructions 2019-04-29 10:47:01 +02:00
pci_irq.c s390/pci: do not set affinity for floating irqs 2020-04-22 16:20:55 +02:00
pci_mmio.c mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
pci_sysfs.c s390/pci: create zPCI bus 2020-04-28 13:49:46 +02:00