[PATCH 4.19 008/205] powerpc/eeh: Fix possible null deref in eeh_dump_dev_log()

Greg Kroah-Hartman
2018-11-19T16:31:15Z

From: Sam Bobroff <sbobroff@linux.ibm.com>

[ Upstream commit f9bc28aedfb5bbd572d2d365f3095c1becd7209b ]

If an error occurs during an unplug operation, it's possible for
eeh_dump_dev_log() to be called when edev->pdn is null, which
currently leads to dereferencing a null pointer.

Handle this by skipping the error log for those devices.

Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/kernel/eeh.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -169,6 +169,11 @@ static size_t eeh_dump_dev_log(struct ee
int n = 0, l = 0;
char buffer[128];

+ if (!pdn) {
+ pr_warn("EEH: Note: No error log for absent device.\n");
+ return 0;
+ }
+
n += scnprintf(buf+n, len-n, "%04x:%02x:%02x.%01x\n",
pdn->phb->global_number, pdn->busno,
PCI_SLOT(pdn->devfn), PCI_FUNC(pdn->devfn));