From: Sam Bobroff <sbobroff@linux.ibm.com>
Date: Fri, 25 May 2018 03:11:30 +0000 (+1000)
Subject: powerpc/eeh: Fix use-after-release of EEH driver
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=bc0b4615cc975db67ace25e9e8cc7f7dcf207d6b;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

powerpc/eeh: Fix use-after-release of EEH driver

[ Upstream commit 46d4be41b987a6b2d25a2ebdd94cafb44e21d6c5 ]

Correct two cases where eeh_pcid_get() is used to reference the driver's
module but the reference is dropped before the driver pointer is used.

In eeh_rmv_device() also refactor a little so that only two calls to
eeh_pcid_put() are needed, rather than three and the reference isn't
taken at all if it wasn't needed.

Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
index ca2243df9cb2..470284f9e4f6 100644
--- a/arch/powerpc/kernel/eeh_driver.c
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -450,9 +450,11 @@ static void *eeh_add_virt_device(void *data, void *userdata)
 
 	driver = eeh_pcid_get(dev);
 	if (driver) {
-		eeh_pcid_put(dev);
-		if (driver->err_handler)
+		if (driver->err_handler) {
+			eeh_pcid_put(dev);
 			return NULL;
+		}
+		eeh_pcid_put(dev);
 	}
 
 #ifdef CONFIG_PPC_POWERNV
@@ -489,17 +491,19 @@ static void *eeh_rmv_device(void *data, void *userdata)
 	if (eeh_dev_removed(edev))
 		return NULL;
 
-	driver = eeh_pcid_get(dev);
-	if (driver) {
-		eeh_pcid_put(dev);
-		if (removed &&
-		    eeh_pe_passed(edev->pe))
-			return NULL;
-		if (removed &&
-		    driver->err_handler &&
-		    driver->err_handler->error_detected &&
-		    driver->err_handler->slot_reset)
+	if (removed) {
+		if (eeh_pe_passed(edev->pe))
 			return NULL;
+		driver = eeh_pcid_get(dev);
+		if (driver) {
+			if (driver->err_handler &&
+			    driver->err_handler->error_detected &&
+			    driver->err_handler->slot_reset) {
+				eeh_pcid_put(dev);
+				return NULL;
+			}
+			eeh_pcid_put(dev);
+		}
 	}
 
 	/* Remove it from PCI subsystem */