From f25a7ece08bdb1f2b3c4bbeae942682fc3a99dde Mon Sep 17 00:00:00 2001 From: Michael Kelley Date: Fri, 10 Aug 2018 23:06:11 +0000 Subject: Drivers: hv: vmbus: Fix synic per-cpu context initialization If hv_synic_alloc() errors out, the state of the per-cpu context for some CPUs is unknown since the zero'ing is done as each CPU is iterated over. In such case, hv_synic_cleanup() may try to free memory based on uninitialized values. Fix this by zero'ing the per-cpu context for all CPUs before doing any memory allocations that might fail. Signed-off-by: Michael Kelley Reported-by: Dan Carpenter Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/hv.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'drivers/hv') diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 748a1c4172a6..332d7c34be5c 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -189,6 +189,17 @@ static void hv_init_clockevent_device(struct clock_event_device *dev, int cpu) int hv_synic_alloc(void) { int cpu; + struct hv_per_cpu_context *hv_cpu; + + /* + * First, zero all per-cpu memory areas so hv_synic_free() can + * detect what memory has been allocated and cleanup properly + * after any failures. + */ + for_each_present_cpu(cpu) { + hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu); + memset(hv_cpu, 0, sizeof(*hv_cpu)); + } hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask), GFP_KERNEL); @@ -198,10 +209,8 @@ int hv_synic_alloc(void) } for_each_present_cpu(cpu) { - struct hv_per_cpu_context *hv_cpu - = per_cpu_ptr(hv_context.cpu_context, cpu); + hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu); - memset(hv_cpu, 0, sizeof(*hv_cpu)); tasklet_init(&hv_cpu->msg_dpc, vmbus_on_msg_dpc, (unsigned long) hv_cpu); -- cgit