From: Michael S. Tsirkin Date: Wed, 3 Jan 2007 12:46:30 +0000 (+0200) Subject: IB/mthca: Fix off-by-one in FMR handling on memfree X-Git-Tag: v2.6.20-rc5~31^2~7 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=46707e96b7254663139225ab6c9ab9922cd8c435;p=linux-2.6 IB/mthca: Fix off-by-one in FMR handling on memfree 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 --- diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c index 15cc2f6eb4..6b19645d94 100644 --- a/drivers/infiniband/hw/mthca/mthca_memfree.c +++ b/drivers/infiniband/hw/mthca/mthca_memfree.c @@ -232,7 +232,7 @@ void *mthca_table_find(struct mthca_icm_table *table, int obj) 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; }