From: Michael Kelley mikelley@microsoft.com
[ Upstream commit f25a7ece08bdb1f2b3c4bbeae942682fc3a99dde ]
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 mikelley@microsoft.com Reported-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: K. Y. Srinivasan kys@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hv/hv.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index fe041f22521da..23f312b4c6aa2 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -148,6 +148,17 @@ 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 = kzalloc(sizeof(struct cpumask) * nr_node_ids, GFP_ATOMIC); @@ -157,10 +168,8 @@ 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);