From 8c9eb0e3731d7140abc77cd80aeeeea8c2ff325e Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Thu, 5 May 2022 08:35:31 +0200 Subject: [PATCH] xen/grant-table: never put a reserved grant on the free list Make sure a reserved grant is never put on the free list, as this could cause hard to debug errors. Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross --- drivers/xen/grant-table.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 6ea31ea..1a1aec0 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -207,6 +207,10 @@ static inline void check_free_callbacks(void) static void put_free_entry(grant_ref_t ref) { unsigned long flags; + + if (unlikely(ref < GNTTAB_NR_RESERVED_ENTRIES)) + return; + spin_lock_irqsave(&gnttab_list_lock, flags); gnttab_entry(ref) = gnttab_free_head; gnttab_free_head = ref; -- 2.7.4