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authorMichael Kelley <mikelley@microsoft.com>2020-09-13 12:47:29 -0700
committerWei Liu <wei.liu@kernel.org>2020-09-14 11:42:33 +0000
commit911e1987efc8f3e6445955fbae7f54b428b92bd3 (patch)
treef513da7f15a88350919e084894fe41f00b5f3991 /drivers/hv
parent19873eec7e13fda140a0ebc75d6664e57c00bfb1 (diff)
Drivers: hv: vmbus: Add timeout to vmbus_wait_for_unload
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 <mikelley@microsoft.com> Reviewed-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Link: https://lore.kernel.org/r/1600026449-23651-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/channel_mgmt.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 417a95e5094d..af7832e13167 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -750,7 +750,7 @@ 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
@@ -760,8 +760,11 @@ 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;