From: Mohammed Gamal <mgamal@xxxxxxxxxx>
[ Upstream commit 1eb65c8687316c65140b48fad27133d583178e15 ]
relid2channel() assumes vmbus channel array to be allocated when called.
However, in cases such as kdump/kexec, not all relids will be reset by the host.
When the second kernel boots and if the guest receives a vmbus interrupt during
vmbus driver initialization before vmbus_connect() is called, before it finishes,
or if it fails, the vmbus interrupt service routine is called which in turn calls
relid2channel() and can cause a null pointer dereference.
Print a warning and error out in relid2channel() for a channel id that's invalid
in the second kernel.
Fixes: 8b6a877c060e ("Drivers: hv: vmbus: Replace the per-CPU channel lists with a global array of channels")
Signed-off-by: Mohammed Gamal <mgamal@xxxxxxxxxx>
Reviewed-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230217204411.212709-1-mgamal@xxxxxxxxxx
Signed-off-by: Wei Liu <wei.liu@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/hv/connection.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index bfd7f00a59ecf..683fdfa3e723e 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -305,6 +305,10 @@ void vmbus_disconnect(void)
*/
struct vmbus_channel *relid2channel(u32 relid)
{
+ if (vmbus_connection.channels == NULL) {
+ pr_warn_once("relid2channel: relid=%d: No channels mapped!\n", relid);
+ return NULL;
+ }
if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
return NULL;
return READ_ONCE(vmbus_connection.channels[relid]);
--
2.39.2
