A bug can be triggered by following command
$ modprobe nd_pmem && modprobe -r nd_pmem
[ 10.060014] BUG dax_cache (Not tainted): Objects remaining in dax_cache on
__kmem_cache_shutdown()
[ 10.060938] Slab 0x0000000085b729ac objects=9 used=1 fp=0x000000004f5ae469
flags=0x200000000010200(slab|head|node)
[ 10.062433] Call Trace:
[ 10.062673] dump_stack_lvl+0x34/0x44
[ 10.062865] slab_err+0x90/0xd0
[ 10.063619] __kmem_cache_shutdown+0x13b/0x2f0
[ 10.063848] kmem_cache_destroy+0x4a/0x110
[ 10.064058] __x64_sys_delete_module+0x265/0x300
This is caused by dax_fs_exit() not flushing inodes before destroy cache.
To fix this issue, call rcu_barrier() before destroy cache.
Signed-off-by: Tong Zhang <ztong0...@gmail.com>
---
drivers/dax/super.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index e3029389d809..6bd565fe2e63 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -476,6 +476,7 @@ static int dax_fs_init(void)
static void dax_fs_exit(void)
{
kern_unmount(dax_mnt);
+ rcu_barrier();
kmem_cache_destroy(dax_cache);
}
--
2.25.1
