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

From: Greg Kroah-Hartman
Date: Thu Apr 16 2020 - 09:57:19 EST


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)