In the SMP guest case, when the per-channel callback hvsock_events() is
running on virtual CPU A, if the guest tries to close the connection on
virtual CPU B: we invoke vmbus_close() -> vmbus_close_internal(),
then we can have trouble: on B, vmbus_close_internal() will send IPI
reset_channel_cb() to A, trying to set channel->onchannel_callbackto NULL;
on A, if the IPI handler happens between
"if (channel->onchannel_callback != NULL)" and invoking
channel->onchannel_callback, we'll invoke a function pointer of NULL.
This is why the patch is necessary.
Signed-off-by: Dexuan Cui <de...@microsoft.com>
---
drivers/hv/connection.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 4fc2e88..4766fd8 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -319,6 +319,9 @@ static void process_chn_event(u32 relid)
void *arg;
bool read_state;
u32 bytes_to_read;
+ bool is_hvsock = false;
+
+ local_irq_disable();
/*
* Find the channel based on this relid and invokes the
@@ -327,7 +330,11 @@ static void process_chn_event(u32 relid)
channel = pcpu_relid2channel(relid);
if (!channel)
- return;
+ goto out;
+
+ is_hvsock = is_hvsock_channel(channel);
+ if (!is_hvsock)
+ local_irq_enable();
/*
* A channel once created is persistent even when there
@@ -363,6 +370,12 @@ static void process_chn_event(u32 relid)
bytes_to_read = 0;
} while (read_state && (bytes_to_read != 0));
}
+
+ /* local_irq_enable() is alredy invoked above */
+ if (!is_hvsock)
+ return;
+out:
+ local_irq_enable();
}
/*
--
2.1.0
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
