From: Michael Kelley <mikel...@microsoft.com>
[ Upstream commit 911e1987efc8f3e6445955fbae7f54b428b92bd3 ]
vmbus_wait_for_unload() looks for a CHANNELMSG_UNLOAD_RESPONSE message
coming from Hyper-V. But if the message isn't found for some reason,
the panic path gets hung forever. Add a timeout of 10 seconds to prevent
this.
Fixes: 415719160de3 ("Drivers: hv: vmbus: avoid scheduling in interrupt context
in vmbus_initiate_unload()")
Signed-off-by: Michael Kelley <mikel...@microsoft.com>
Reviewed-by: Dexuan Cui <de...@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
Link:
https://lore.kernel.org/r/1600026449-23651-1-git-send-email-mikel...@microsoft.com
Signed-off-by: Wei Liu <wei....@kernel.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
drivers/hv/channel_mgmt.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 501c43c5851dc..452307c79e4b9 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -769,7 +769,7 @@ static void vmbus_wait_for_unload(void)
void *page_addr;
struct hv_message *msg;
struct vmbus_channel_message_header *hdr;
- u32 message_type;
+ u32 message_type, i;
/*
* CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
@@ -779,8 +779,11 @@ static void vmbus_wait_for_unload(void)
* functional and vmbus_unload_response() will complete
* vmbus_connection.unload_event. If not, the last thing we can do is
* read message pages for all CPUs directly.
+ *
+ * Wait no more than 10 seconds so that the panic path can't get
+ * hung forever in case the response message isn't seen.
*/
- while (1) {
+ for (i = 0; i < 1000; i++) {
if (completion_done(&vmbus_connection.unload_event))
break;
--
2.25.1
