powerpc/perf: Fix loop exit condition in nest_imc_event_init

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 <[email protected]>

Fixes 885dcd709ba91 ( powerpc/perf: Add nest IMC PMU support)

Signed-off-by Anju T Sudhakar <[email protected]>

---
  arch/powerpc/perf/imc-pmu.c               | 2 +-
  arch/powerpc/platforms/powernv/opal-imc.c | 2 +-
  2 files changed, 2 insertions(+), 2 deletions(-)

arch/powerpc/perf/imc-pmu.c +1 -1

index 4f34c75..d1009fe 100644
@@ -508,7 +508,7 @@ static int nest_imc_event_init(struct perf_event *event)
  			break;
  		}
  		pcni++;
-	} while (pcni);
+	} while (pcni->vbase != 0);
 
  	if (!flag)
  		return -ENODEV;

arch/powerpc/platforms/powernv/opal-imc.c +1 -1

index 58a0794..3d27f02 100644
@@ -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;

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 <[email protected]>

Fixes 885dcd709ba91 ( powerpc/perf: Add nest IMC PMU support)

Signed-off-by Anju T Sudhakar <[email protected]>

Reviewed-by Madhavan Srinivasan <[email protected]>