From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- drivers/dma/idxd/defaults.c | 51 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 drivers/dma/idxd/defaults.c (limited to 'drivers/dma/idxd/defaults.c') diff --git a/drivers/dma/idxd/defaults.c b/drivers/dma/idxd/defaults.c new file mode 100644 index 000000000..2bbbcd02a --- /dev/null +++ b/drivers/dma/idxd/defaults.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright(c) 2023 Intel Corporation. All rights rsvd. */ +#include +#include "idxd.h" + +int idxd_load_iaa_device_defaults(struct idxd_device *idxd) +{ + struct idxd_engine *engine; + struct idxd_group *group; + struct idxd_wq *wq; + + if (!test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags)) + return 0; + + wq = idxd->wqs[0]; + + if (wq->state != IDXD_WQ_DISABLED) + return -EPERM; + + /* set mode to "dedicated" */ + set_bit(WQ_FLAG_DEDICATED, &wq->flags); + wq->threshold = 0; + + /* only setting up 1 wq, so give it all the wq space */ + wq->size = idxd->max_wq_size; + + /* set priority to 10 */ + wq->priority = 10; + + /* set type to "kernel" */ + wq->type = IDXD_WQT_KERNEL; + + /* set wq group to 0 */ + group = idxd->groups[0]; + wq->group = group; + group->num_wqs++; + + /* set name to "iaa_crypto" */ + strscpy_pad(wq->name, "iaa_crypto"); + + /* set driver_name to "crypto" */ + strscpy_pad(wq->driver_name, "crypto"); + + engine = idxd->engines[0]; + + /* set engine group to 0 */ + engine->group = idxd->groups[0]; + engine->group->num_engines++; + + return 0; +} -- cgit v1.3.1