[PATCH] drivers/xen/grant-table.c: Be sure of unsigned value never comparing with 0

From: Chen Gang
Date: Tue Aug 26 2014 - 11:38:50 EST


In grow_gnttab_list(), 'i' is 'unsigned int', and 'nr_glist_frames' may
be 0 because 'nr_grant_frames' may be 0. So 'i' may never be less than
'nr_glist_frames' in failure processing, which cause infinite looping.

Signed-off-by: Chen Gang <gang.chen.5i5j@xxxxxxxxx>
---
drivers/xen/grant-table.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index c254ae0..be07645 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -592,8 +592,8 @@ static int grow_gnttab_list(unsigned int more_frames)
return 0;

grow_nomem:
- for ( ; i >= nr_glist_frames; i--)
- free_page((unsigned long) gnttab_list[i]);
+ while (i > nr_glist_frames)
+ free_page((unsigned long) gnttab_list[--i]);
return -ENOMEM;
}

--
1.9.3
--
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