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authorFrederic Barrat <fbarrat@linux.ibm.com>2019-10-16 18:28:33 +0200
committerMichael Ellerman <mpe@ellerman.id.au>2019-10-25 13:08:50 +0200
commita8a30219ba78b1abb92091102b632f8e9bbdbf03 (patch)
tree6e34fa1e495322a06529b3afd114139ae1f779c9 /arch
parentpowerpc/32s: fix allow/prevent_user_access() when crossing segment boundaries. (diff)
downloadlinux-a8a30219ba78b1abb92091102b632f8e9bbdbf03.tar.xz
linux-a8a30219ba78b1abb92091102b632f8e9bbdbf03.zip
powerpc/powernv/eeh: Fix oops when probing cxl devices
Recent cleanup in the way EEH support is added to a device causes a kernel oops when the cxl driver probes a device and creates virtual devices discovered on the FPGA: BUG: Kernel NULL pointer dereference at 0x000000a0 Faulting instruction address: 0xc000000000048070 Oops: Kernel access of bad area, sig: 7 [#1] ... NIP eeh_add_device_late.part.9+0x50/0x1e0 LR eeh_add_device_late.part.9+0x3c/0x1e0 Call Trace: _dev_info+0x5c/0x6c (unreliable) pnv_pcibios_bus_add_device+0x60/0xb0 pcibios_bus_add_device+0x40/0x60 pci_bus_add_device+0x30/0x100 pci_bus_add_devices+0x64/0xd0 cxl_pci_vphb_add+0xe0/0x130 [cxl] cxl_probe+0x504/0x5b0 [cxl] local_pci_probe+0x6c/0x110 work_for_cpu_fn+0x38/0x60 The root cause is that those cxl virtual devices don't have a representation in the device tree and therefore no associated pci_dn structure. In eeh_add_device_late(), pdn is NULL, so edev is NULL and we oops. We never had explicit support for EEH for those virtual devices. Instead, EEH events are reported to the (real) pci device and handled by the cxl driver. Which can then forward to the virtual devices and handle dependencies. The fact that we try adding EEH support for the virtual devices is new and a side-effect of the recent cleanup. This patch fixes it by skipping adding EEH support on powernv for devices which don't have a pci_dn structure. The cxl driver doesn't create virtual devices on pseries so this patch doesn't fix it there intentionally. Fixes: b905f8cdca77 ("powerpc/eeh: EEH for pSeries hot plug") Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com> Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20191016162833.22509-1-fbarrat@linux.ibm.com
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/platforms/powernv/eeh-powernv.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c
index 6bc24a47e9ef..6f300ab7f0e9 100644
--- a/arch/powerpc/platforms/powernv/eeh-powernv.c
+++ b/arch/powerpc/platforms/powernv/eeh-powernv.c
@@ -42,7 +42,7 @@ void pnv_pcibios_bus_add_device(struct pci_dev *pdev)
{
struct pci_dn *pdn = pci_get_pdn(pdev);
- if (eeh_has_flag(EEH_FORCE_DISABLED))
+ if (!pdn || eeh_has_flag(EEH_FORCE_DISABLED))
return;
dev_dbg(&pdev->dev, "EEH: Setting up device\n");