Drivers: hv: vmbus: Fix synic per-cpu context initialization (f25a7ece) · Commits · 戴 / test

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>

drivers/hv/hv.c

+12 −3

Original line number	Diff line number	Diff line
		@@ -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);

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