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Subject[patch 11/59] [stable] [PATCH] IB/mthca: Fix off-by-one in FMR handling on memfree
-stable review patch.  If anyone has any objections, please let us know.

From: Michael S. Tsirkin <>

mthca_table_find() will return the wrong address when the table entry
being searched for is exactly at the beginning of a sglist entry
(other than the first), because it uses >= when it should use >.

Example: assume we have 2 entries in scatterlist, 4K each, offset is
4K. The current code will return first entry + 4K when we really want
the second entry.

In particular this means mapping an FMR on a memfree HCA may end up
writing the page table into the wrong place, leading to memory
corruption and also causing the HCA to use an incorrect address
translation table.

Signed-off-by: Michael S. Tsirkin <>
Signed-off-by: Roland Dreier <>
Signed-off-by: Chris Wright <>
This is upstream, and fixes a data corruption/crash bug with storage
over SRP.

drivers/infiniband/hw/mthca/mthca_memfree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-
+++ linux-
@@ -232,7 +232,7 @@ void *mthca_table_find(struct mthca_icm_

list_for_each_entry(chunk, &icm->chunk_list, list) {
for (i = 0; i < chunk->npages; ++i) {
- if (chunk->mem[i].length >= offset) {
+ if (chunk->mem[i].length > offset) {
page = chunk->mem[i].page;
goto out;
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