[PATCH 1/2] dm verity: init fec io before cleaning it

[Wu Bo]

If BIO error, it may goto verity_finish_io() before
verity_fec_init_io(). Therefor, the fec_io->rs is not initialized and
may crash when doing memory freeing in verity_fec_finish_io().

Crash call stack:
 die+0x90/0x2b8
 __do_kernel_fault+0x260/0x298
 do_bad_area+0x2c/0xdc
 do_translation_fault+0x3c/0x54
 do_mem_abort+0x54/0x118
 el1_abort+0x38/0x5c
 el1h_64_sync_handler+0x50/0x90
 el1h_64_sync+0x64/0x6c
 free_rs+0x18/0xac
 fec_rs_free+0x10/0x24
 mempool_free+0x58/0x148
 verity_fec_finish_io+0x4c/0xb0
 verity_end_io+0xb8/0x150

Signed-off-by: Wu Bo <bo.wu@xxxxxxxx>
---
 drivers/md/dm-verity-target.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index e115fcfe723c..42b2483eb08c 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -642,7 +642,6 @@ static void verity_work(struct work_struct *w)
 
 	io->in_tasklet = false;
 
-	verity_fec_init_io(io);
 	verity_finish_io(io, errno_to_blk_status(verity_verify_io(io)));
 }
 
@@ -667,6 +666,7 @@ static void verity_end_io(struct bio *bio)
 {
 	struct dm_verity_io *io = bio->bi_private;
 
+	verity_fec_init_io(io);
 	if (bio->bi_status &&
 	    (!verity_fec_is_enabled(io->v) || verity_is_system_shutting_down())) {
 		verity_finish_io(io, bio->bi_status);
-- 
2.25.1