powerpc/eeh: Fix a bug when pci structure is null
authorBreno Leitao <leitao@linux.vnet.ibm.com>
Wed, 3 Feb 2010 05:56:41 +0000 (05:56 +0000)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Wed, 17 Feb 2010 03:02:47 +0000 (14:02 +1100)
commit8d3d50bf1913561ef3b1f5b53115c5a481ba9b1e
tree31da78f8750942c4ec16de24d63e9834b348fcbf
parente0508b1516ad4423499d4118a9037ae0aa4e9c2f
powerpc/eeh: Fix a bug when pci structure is null

During a EEH recover, the pci_dev structure can be null, mainly if an
eeh event is detected during cpi config operation. In this case, the
pci_dev will not be known (and will be null) the kernel will crash
with the following message:

Unable to handle kernel paging request for data at address 0x000000a0
Faulting instruction address: 0xc00000000006b8b4
Oops: Kernel access of bad area, sig: 11 [#1]

NIP [c00000000006b8b4] .eeh_event_handler+0x10c/0x1a0
LR [c00000000006b8a8] .eeh_event_handler+0x100/0x1a0
Call Trace:
[c0000003a80dff00] [c00000000006b8a8] .eeh_event_handler+0x100/0x1a0
[c0000003a80dff90] [c000000000031f1c] .kernel_thread+0x54/0x70

The bug occurs because pci_name() tries to access a null pointer.
This patch just guarantee that pci_name() is not called on Null pointers.

Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch/powerpc/include/asm/ppc-pci.h
arch/powerpc/platforms/pseries/eeh.c
arch/powerpc/platforms/pseries/eeh_driver.c
arch/powerpc/platforms/pseries/eeh_event.c