On Mon, Oct 04, 2021 at 08:03:55AM +0200, Greg Kroah-Hartman wrote: > On Mon, Oct 04, 2021 at 01:07:46AM +0000, Al Viro wrote: > > On Mon, Oct 04, 2021 at 09:03:53AM +0800, Ian Kent wrote: > > > It's been reported that doing stress test for module insertion and > > > removal can result in an ENOENT from libkmod for a valid module. > > > > > > In kernfs_iop_lookup() a negative dentry is created if there's no kernfs > > > node associated with the dentry or the node is inactive. > > > > > > But inactive kernfs nodes are meant to be invisible to the VFS and > > > creating a negative dentry for these can have unexpected side effects > > > when the node transitions to an active state. > > > > > > The point of creating negative dentries is to avoid the expensive > > > alloc/free cycle that occurs if there are frequent lookups for kernfs > > > attributes that don't exist. So kernfs nodes that are not yet active > > > should not result in a negative dentry being created so when they > > > transition to an active state VFS lookups can create an associated > > > dentry is a natural way. > > > > > > It's also been reported that https://github.com/osandov/blktests.git > > > test block/001 hangs during the test. It was suggested that recent > > > changes to blktests might have caused it but applying this patch > > > resolved the problem without change to blktests. > > > > Looks sane, but which tree should it go through? I can pick it, but I've > > no idea if anybody already has kernfs work in their trees... > > I can take it, kernfs patches normally go through my tree, can I get an > acked-by? ACKed-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
