From: Tong Zhang <ztong0001@xxxxxxxxx> [ Upstream commit a7e8de822e0b1979f08767c751f6c8a9c1d4ad86 ] 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 <ztong0001@xxxxxxxxx> Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Link: https://lore.kernel.org/r/20220212071111.148575-1-ztong0001@xxxxxxxxx Fixes: 7b6be8444e0f ("dax: refactor dax-fs into a generic provider of 'struct dax_device' instances") Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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); } -- 2.34.1
