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Commit b0d54e40 authored by Michael Kelley's avatar Michael Kelley Committed by Greg Kroah-Hartman
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Drivers: hv: vmbus: Fix synic per-cpu context initialization 



[ 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: default avatarMichael Kelley <mikelley@microsoft.com>
Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent a1d374ea

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);