dm: cope with access beyond end of device in dm_merge_bvec
If for any reason dm_merge_bvec() is given an offset beyond the end of the
device, avoid an oops and always allow one page to be added to an empty bio.
We'll reject the I/O later after the bio is submitted.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 469cec5..ace998c 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -843,6 +843,8 @@
goto out;
ti = dm_table_find_target(map, bvm->bi_sector);
+ if (!dm_target_is_valid(ti))
+ goto out_table;
/*
* Find maximum amount of I/O that won't need splitting
@@ -861,6 +863,7 @@
if (max_size && ti->type->merge)
max_size = ti->type->merge(ti, bvm, biovec, max_size);
+out_table:
dm_table_put(map);
out: