nvmet-fc: fix invalid free in LS IOD error path

commit ba98d67 upstream.

nvmet_fc_alloc_ls_iodlist() advances iod while initializing the LS IOD
array. If an rqstbuf allocation or response buffer DMA mapping fails,
the unwind loop decrements iod past the start of the array. The final
kfree(iod) therefore frees an address before the allocated object.

This can be reproduced with nvme-fcloop and failslab by setting
fail-nth to 6 before creating a target port. KASAN reports:

  BUG: KASAN: invalid-free in nvmet_fc_register_targetport
  Free of addr ffff88816cf8ff48 by task nvmet_fail_nth/9552

Free the original allocation base stored in tgtport->iod instead. With
this fix applied, the same sysfs write with fail-nth=6 returns -ENOMEM
without any KASAN report.

Fixes: c534320 ("nvme-fabrics: Add target support for FC transport")
Cc: stable@vger.kernel.org
Reviewed-by: Maurizio Lombardi <mlombard@redhat.com>
Assisted-by: Codex:gpt-5
Signed-off-by: Jiang HongHui <jiang_hh2019@163.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Forget-Glow

drivers/nvme/target/fc.c

@@ -571,7 +571,7 @@ nvmet_fc_alloc_ls_iodlist(struct nvmet_fc_tgtport *tgtport)
 		list_del(&iod->ls_rcv_list);
 	}
 
-	kfree(iod);
+	kfree(tgtport->iod);
 
 	return -EFAULT;
 }