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Drivers: vmbus: Check for channel allocation before looking up relids

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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: 8b6a877c06 ("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>
This commit is contained in:
Mohammed Gamal 2023-02-17 22:44:11 +02:00 • committed by Wei Liu
parent fe15c26ee2
commit 1eb65c8687
1 changed files with 4 additions and 0 deletions
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4
drivers/hv/connection.c
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@ -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]);