[PATCH 5.5 182/257] dm verity fec: fix memory leak in verity_fec_dtr

[Greg Kroah-Hartman]

From: Shetty, Harshini X (EXT-Sony Mobile) <Harshini.X.Shetty@xxxxxxxx>

commit 75fa601934fda23d2f15bf44b09c2401942d8e15 upstream.

Fix below kmemleak detected in verity_fec_ctr. output_pool is
allocated for each dm-verity-fec device. But it is not freed when
dm-table for the verity target is removed. Hence free the output
mempool in destructor function verity_fec_dtr.

unreferenced object 0xffffffffa574d000 (size 4096):
  comm "init", pid 1667, jiffies 4294894890 (age 307.168s)
  hex dump (first 32 bytes):
    8e 36 00 98 66 a8 0b 9b 00 00 00 00 00 00 00 00  .6..f...........
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<0000000060e82407>] __kmalloc+0x2b4/0x340
    [<00000000dd99488f>] mempool_kmalloc+0x18/0x20
    [<000000002560172b>] mempool_init_node+0x98/0x118
    [<000000006c3574d2>] mempool_init+0x14/0x20
    [<0000000008cb266e>] verity_fec_ctr+0x388/0x3b0
    [<000000000887261b>] verity_ctr+0x87c/0x8d0
    [<000000002b1e1c62>] dm_table_add_target+0x174/0x348
    [<000000002ad89eda>] table_load+0xe4/0x328
    [<000000001f06f5e9>] dm_ctl_ioctl+0x3b4/0x5a0
    [<00000000bee5fbb7>] do_vfs_ioctl+0x5dc/0x928
    [<00000000b475b8f5>] __arm64_sys_ioctl+0x70/0x98
    [<000000005361e2e8>] el0_svc_common+0xa0/0x158
    [<000000001374818f>] el0_svc_handler+0x6c/0x88
    [<000000003364e9f4>] el0_svc+0x8/0xc
    [<000000009d84cec9>] 0xffffffffffffffff

Fixes: a739ff3f543af ("dm verity: add support for forward error correction")
Depends-on: 6f1c819c219f7 ("dm: convert to bioset_init()/mempool_init()")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Harshini Shetty <harshini.x.shetty@xxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/md/dm-verity-fec.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/md/dm-verity-fec.c
+++ b/drivers/md/dm-verity-fec.c
@@ -551,6 +551,7 @@ void verity_fec_dtr(struct dm_verity *v)
 	mempool_exit(&f->rs_pool);
 	mempool_exit(&f->prealloc_pool);
 	mempool_exit(&f->extra_pool);
+	mempool_exit(&f->output_pool);
 	kmem_cache_destroy(f->cache);
 
 	if (f->data_bufio)