From: Mohammed Gamal mgamal@redhat.com
[ 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@redhat.com Reviewed-by: Dexuan Cui decui@microsoft.com Link: https://lore.kernel.org/r/20230217204411.212709-1-mgamal@redhat.com Signed-off-by: Wei Liu wei.liu@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hv/connection.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c index 9dc27e5d367a2..da51b50787dff 100644 --- a/drivers/hv/connection.c +++ b/drivers/hv/connection.c @@ -409,6 +409,10 @@ 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]);