[PATCH][next] afs: fix a dereference on pointer cell before cell is null checked

[David Howells]

Colin King <colin.king at canonical.com> wrote:

> @@ -606,7 +605,7 @@ void afs_unuse_cell(struct afs_net *net, struct afs_cell *cell, enum afs_cell_tr
>  
>  	u = atomic_read(&cell->ref);
>  	a = atomic_dec_return(&cell->active);
> -	trace_afs_cell(debug_id, u, a, reason);
> +	trace_afs_cell(cell->debug_id, u, a, reason);

It's probably better to read cell->debug_id before calling
atomic_dec_return().

I have a patch for this based on a report by Dan Carpenter, so no need to send
a revised patch.

Thanks,
David