null_alloc_dev() allocates memory for dev->badblocks, but cleanup
currently only occurs in the configfs release codepath, missing a number
of other places.
This bug was found running the blktests block/010 test, alongside
kmemleak:
rapido1:/blktests# ./check block/010
...
rapido1:/blktests# echo scan > /sys/kernel/debug/kmemleak
[ 306.966708] kmemleak: 32 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
rapido1:/blktests# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff88001f86d000 (size 4096):
comm "modprobe", pid 231, jiffies 4294892415 (age 318.252s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff814b0379>] kmemleak_alloc+0x49/0xa0
[<ffffffff810f180f>] kmem_cache_alloc+0x9f/0xe0
[<ffffffff8124e45f>] badblocks_init+0x2f/0x60
[<ffffffffa0019fae>] 0xffffffffa0019fae
[<ffffffffa0021273>] nullb_device_badblocks_store+0x63/0x130 [null_blk]
[<ffffffff810004cd>] do_one_initcall+0x3d/0x170
[<ffffffff8109fe0d>] do_init_module+0x56/0x1e9
[<ffffffff8109ebd7>] load_module+0x1c47/0x26a0
[<ffffffff8109f819>] SyS_finit_module+0xa9/0xd0
[<ffffffff814b4f60>] entry_SYSCALL_64_fastpath+0x13/0x94
Fixes: 2f54a613c942 ("nullb: badbblocks support")
Signed-off-by: David Disseldorp <ddiss@xxxxxxx>
---
drivers/block/null_blk.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 8042c26ea9e6..fc80354477c6 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -467,7 +467,6 @@ static void nullb_device_release(struct config_item *item)
{
struct nullb_device *dev = to_nullb_device(item);
- badblocks_exit(&dev->badblocks);
null_free_device_storage(dev, false);
null_free_dev(dev);
}
@@ -578,6 +577,10 @@ static struct nullb_device *null_alloc_dev(void)
static void null_free_dev(struct nullb_device *dev)
{
+ if (!dev)
+ return;
+
+ badblocks_exit(&dev->badblocks);
kfree(dev);
}
--
2.13.6
