[ofa-general] [PATCH/RFC 2/2] IB/mthca: Avoid integer overflow when allocating huge ICM table
Roland Dreier
rdreier at cisco.com
Fri Mar 21 13:58:28 PDT 2008
In mthca_alloc_icm_table(), the number of entries to allocate for the
table->icm array is computed by calculating obj_size * nobj and then
dividing by MTHCA_TABLE_CHUNK_SIZE. If nobj is really large, then
obj_size * nobj may overflow and the division may get the wrong value
(even a negative value). Fix this by calculating the number of
objects per chunk and then dividing nobj by this value instead.
This patch allows crazy configurations such as loading ib_mthca with
the module parameter num_mtt=33554432 to work properly.
Signed-off-by: Roland Dreier <rolandd at cisco.com>
---
drivers/infiniband/hw/mthca/mthca_memfree.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c
index d7d502d..b224079 100644
--- a/drivers/infiniband/hw/mthca/mthca_memfree.c
+++ b/drivers/infiniband/hw/mthca/mthca_memfree.c
@@ -359,12 +359,14 @@ struct mthca_icm_table *mthca_alloc_icm_table(struct mthca_dev *dev,
int use_lowmem, int use_coherent)
{
struct mthca_icm_table *table;
+ int obj_per_chunk;
int num_icm;
unsigned chunk_size;
int i;
u8 status;
- num_icm = (obj_size * nobj + MTHCA_TABLE_CHUNK_SIZE - 1) / MTHCA_TABLE_CHUNK_SIZE;
+ obj_per_chunk = MTHCA_TABLE_CHUNK_SIZE / obj_size;
+ num_icm = DIV_ROUND_UP(nobj, obj_per_chunk);
table = kmalloc(sizeof *table + num_icm * sizeof *table->icm, GFP_KERNEL);
if (!table)
--
1.5.4.3
More information about the general
mailing list