From 860b7d2286236170a36f94946d03ca9888d32571 Mon Sep 17 00:00:00 2001
From: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Date: Tue, 18 Dec 2018 11:50:41 +0530
Subject: [PATCH] powerpc/perf: Fix loop exit condition in nest_imc_event_init

References: FATE#322448, bsc#1054914, git-fixes
Patch-mainline: v5.2-rc1
Git-commit: 860b7d2286236170a36f94946d03ca9888d32571

The data structure (i.e struct imc_mem_info) to hold the memory address
information for nest imc units is allocated based on the number of nodes
in the system.

nest_imc_event_init() traverse this struct array to calculate the memory
base address for the event-cpu. If we fail to find a match for the event
cpu's chip-id in imc_mem_info struct array, then the do-while loop will
iterate until we crash.

Fix this by changing the loop exit condition based on the number of
non zero vbase elements in the array, since the allocation is done for
nr_chips + 1.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 885dcd709ba91 ("powerpc/perf: Add nest IMC PMU support")
Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/perf/imc-pmu.c               | 2 +-
 arch/powerpc/platforms/powernv/opal-imc.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index 6159e9edddfd..2d12f0037e3a 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -499,7 +499,7 @@ static int nest_imc_event_init(struct perf_event *event)
 			break;
 		}
 		pcni++;
-	} while (pcni);
+	} while (pcni->vbase != 0);
 
 	if (!flag)
 		return -ENODEV;
diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c
index 58a07948c76e..3d27f02695e4 100644
--- a/arch/powerpc/platforms/powernv/opal-imc.c
+++ b/arch/powerpc/platforms/powernv/opal-imc.c
@@ -127,7 +127,7 @@ static int imc_get_mem_addr_nest(struct device_node *node,
 								nr_chips))
 		goto error;
 
-	pmu_ptr->mem_info = kcalloc(nr_chips, sizeof(*pmu_ptr->mem_info),
+	pmu_ptr->mem_info = kcalloc(nr_chips + 1, sizeof(*pmu_ptr->mem_info),
 				    GFP_KERNEL);
 	if (!pmu_ptr->mem_info)
 		goto error;
-- 
2.35.3