On Wed, Aug 06, 2025 at 02:20:56PM +0200, Stefan Metzmacher wrote:
> Hi Dan,
>
> > The mempool_free() function frees "request". Don't free the request
> > until after smbd_disconnect_rdma_connection() to avoid a use after free
> > bug.
> >
> > Fixes: 5e65668c75c0 ("smb: client: let send_done() cleanup before calling smbd_disconnect_rdma_connection()")
> > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > ---
> > fs/smb/client/smbdirect.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/smb/client/smbdirect.c b/fs/smb/client/smbdirect.c
> > index 58321e483a1a..162f8d1c548a 100644
> > --- a/fs/smb/client/smbdirect.c
> > +++ b/fs/smb/client/smbdirect.c
> > @@ -286,8 +286,8 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc)
> > if (wc->status != IB_WC_SUCCESS || wc->opcode != IB_WC_SEND) {
> > log_rdma_send(ERR, "wc->status=%d wc->opcode=%d\n",
> > wc->status, wc->opcode);
> > - mempool_free(request, request->info->request_mempool);
> > smbd_disconnect_rdma_connection(request->info);
> > + mempool_free(request, request->info->request_mempool);
>
> The correct fix is to use 'info' instead of 'request->info'
> other than that the order needs to stay that way.
>
> I already asked Steve to squash such a change into the
> original commit (which is not yet upstream).
>
> See:
> https://lore.kernel.org/linux-cifs/cover.1754308712.git.metze@xxxxxxxxx/T/#m98a8607d7b83a11fd78547306836a872a2a27192
>
> What was the test that triggered the problem?
> Or did you only noticed it by looking at the code?
This was a Smatch static checker warning. You need to have the cross
function DB to detect it.
regards,
dan carpenter
