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

[Colin Ian King]

On 27/10/2020 11:05, David Howells wrote:
> 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.

OK - thanks David
> 
> Thanks,
> David
>