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authorJun'ichi Nomura <j-nomura@ce.jp.nec.com>2007-12-13 14:15:25 +0000
committerAlasdair G Kergon <agk@redhat.com>2007-12-20 17:32:08 +0000
commit512875bd9661368da6f993205a61213b79ba1df0 (patch)
tree7a2e010060b6233cd02e2e36b62f5dcaa96c2c36 /drivers/md/dm-ioctl.c
parentfbdcf18df73758b2e187ab94678b30cd5f6ff9f9 (diff)
dm: table detect io beyond device
This patch fixes a panic on shrinking a DM device if there is outstanding I/O to the part of the device that is being removed. (Normally this doesn't happen - a filesystem would be resized first, for example.) The bug is that __clone_and_map() assumes dm_table_find_target() always returns a valid pointer. It may fail if a bio arrives from the block layer but its target sector is no longer included in the DM btree. This patch appends an empty entry to table->targets[] which will be returned by a lookup beyond the end of the device. After calling dm_table_find_target(), __clone_and_map() and target_message() check for this condition using dm_target_is_valid(). Sample test script to trigger oops:
Diffstat (limited to 'drivers/md/dm-ioctl.c')
-rw-r--r--drivers/md/dm-ioctl.c10
1 files changed, 3 insertions, 7 deletions
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 138200bf5e0..be730fdd483 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1250,21 +1250,17 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
if (!table)
goto out_argv;
- if (tmsg->sector >= dm_table_get_size(table)) {
+ ti = dm_table_find_target(table, tmsg->sector);
+ if (!dm_target_is_valid(ti)) {
DMWARN("Target message sector outside device.");
r = -EINVAL;
- goto out_table;
- }
-
- ti = dm_table_find_target(table, tmsg->sector);
- if (ti->type->message)
+ } else if (ti->type->message)
r = ti->type->message(ti, argc, argv);
else {
DMWARN("Target type does not support messages");
r = -EINVAL;
}
- out_table:
dm_table_put(table);
out_argv:
kfree(argv);