diff options
Diffstat (limited to 'drivers/hv')
| -rw-r--r-- | drivers/hv/channel.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index c4dcab048cb8..f7f3d5ccd6bd 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -28,6 +28,7 @@ #include <linux/module.h> #include <linux/hyperv.h> #include <linux/uio.h> +#include <linux/interrupt.h> #include "hyperv_vmbus.h" @@ -496,8 +497,21 @@ static void reset_channel_cb(void *arg) static int vmbus_close_internal(struct vmbus_channel *channel) { struct vmbus_channel_close_channel *msg; + struct tasklet_struct *tasklet; int ret; + /* + * process_chn_event(), running in the tasklet, can race + * with vmbus_close_internal() in the case of SMP guest, e.g., when + * the former is accessing channel->inbound.ring_buffer, the latter + * could be freeing the ring_buffer pages. + * + * To resolve the race, we can serialize them by disabling the + * tasklet when the latter is running here. + */ + tasklet = hv_context.event_dpc[channel->target_cpu]; + tasklet_disable(tasklet); + channel->state = CHANNEL_OPEN_STATE; channel->sc_creation_callback = NULL; /* Stop callback and cancel the timer asap */ @@ -525,7 +539,7 @@ static int vmbus_close_internal(struct vmbus_channel *channel) * If we failed to post the close msg, * it is perhaps better to leak memory. */ - return ret; + goto out; } /* Tear down the gpadl for the channel's ring buffer */ @@ -538,7 +552,7 @@ static int vmbus_close_internal(struct vmbus_channel *channel) * If we failed to teardown gpadl, * it is perhaps better to leak memory. */ - return ret; + goto out; } } @@ -555,6 +569,9 @@ static int vmbus_close_internal(struct vmbus_channel *channel) if (channel->rescind) hv_process_channel_removal(channel, channel->offermsg.child_relid); +out: + tasklet_enable(tasklet); + return ret; } |